Isoprenoid production

ABSTRACT

The present invention relates to an isolated DNA sequence encoding an enzyme in the mevalonate pathway or the pathway from isopentenyl pyrophosphate to farnesyl pyrophosphate. Vectors and plasmids including such DNA are also set forth. The invention also includes host cells transformed by such DNAs, or vectors or plasmids containing such DNAs. A process for the production of isoprenoids and carotenoids using such transformed host cells is also provided.

This division of application Ser. No. 09/306,595, filed May 6, 1999, now U.S. Pat. No. 6,284,506.

FIELD OF THE INVENTION

The present invention relates to the manufacture of isoprenoids using molecular biology techniques. In particular, the present invention provides DNAs, vectors and host cells for the efficient production of various enzymes in the mevalonate pathway or for converting isopentyl pyrophosphate to farnesyl pyrophosphate synthase.

BACKGROUND OF THE INVENTION

Astaxanthin is reportedly distributed in a wide variety of organisms such as animals (e.g., birds, such as flamingo and scarlet ibis; fish, such as rainbow trout and salmon), algae and microorganisms. It is also reported that astaxanthin has a strong antioxidation property against oxygen radicals, which is believed to be pharmaceutically useful for protecting living cells against some diseases such as a cancer. Moreover, from a commercial prospective, there is an increasing demand for astaxanthin as a coloring reagent especially in the fish farming industry, such as salmon farming, because astaxanthin imparts a distinctive orange-red coloration to the fish and contributes to consumer appeal.

Phaffia rhodozyma is known as a carotenogenic yeast strain which produces astaxanthin specifically. Different from the other carotenogenic yeast, Rhodotorula species, such as Phaffia rhodozyma (P. rhodozyma) can ferment some sugars such as D-glucose. This is a commercially important feature. In a recent taxonomic study, the sexual cycle of P. rhodozyma was revealed and its telemorphic state was designated as Xanthophyllomyces dendrorhous (W. I. Golubev; Yeast 11, 101-110, 1995). Some strain improvement studies to obtain hyper-producers of astaxanthin from P. rhodozyma have been conducted, but such efforts have been restricted to conventional methods including mutagenesis and protoplast fusion in this decade.

Recently, Wery et al. reportedly developed a host vector system using P. rhodozyma in which a non-replicable plasmid was integrated into the genome of P. rhodozyma at the locus of a ribosomal DNA in multiple copies (Wery et al., Gene, 184, 89-97, 1997). Verdoes et al. reported vectors for obtaining a transformant of P. rhodozyma, as well as its three carotenogenic genes which code for the enzymes that catalyze the reactions from geranylgeranyl pyrophosphate to β-carotene (International patent WO97/23633).

It has been reported that the carotenogenic pathway from a general metabolite, acetyl-CoA consists of multiple enzymatic steps in carotenogenic eukaryotes as shown in FIG. 1. In this pathway, two molecules of acetyl-CoA are condensed to yield acetoacetyl-CoA which is converted to 3-hydroxy-3-methyglutaryl-CoA (HMG-CoA) by the action of 3-hydroxymethyl-3-glutaryl-CoA synthas. Next, 3-hydroxy-3-methylglutaryl-CoA reductase converts HMG-CoA to mevalonate, to which two molecules of phosphate residues are then added by the action of two kinases (mevalonate kinase and phosphomevalonate kinase). Mevalonate pyrophosphate is then decarboxylated by the action of mevalonate pyrophosphate decarboxylase to yield isopentenyl pyrophosphate (IPP) which becomes a building unit for a wide variety of isoprene molecules which are necessary in living organisms. This pathway is designated the “mevalonate pathway” taken from its important intermediate, mevalonate.

In this pathway, IPP is isomerized to dimethylaryl pyrophosphate (DMAPP) by the action of IPP isomerase. Then, IPP and DMAPP are converted to a C₁₀ unit, geranyl pyrophosphate (GPP) by a head to tail condensation. In a similar condensation reaction between GPP and IPP, GPP is converted to a C₁₅ unit, farnesyl pyrophosphate (FPP) which is an important substrate of cholesterol in animals, of ergosterol in yeast, and of the farnesylation of regulation proteins, such as the RAS protein. In general, the biosynthesis of GPP and FPP from IPP and DMAPP are catalyzed by one enzyme called FPP synthase (Laskovics et al., Biochemistry, 20, 1893-1901, 1981).

On the other hand, in prokaryotes such as eubacteria, isopentenyl pyrophosphate is reportedly synthesized in a different pathway via 1-deoxyxylulose-5-phosphate from pyruvate which is absent in yeast and animals (Rohmer et al., Biochem. J., 295, 517-524, 1993).

SUMMARY OF THE INVENTION

In studies of cholesterol biosynthesis, it was shown that the rate-limiting steps of cholesterol metabolism were in the steps of this mevalonate pathway, especially in its early steps catalyzed by HMG-CoA synthase and HMG-CoA reductase. It was recognized in accordance with the present invention that the biosynthetic pathways of cholesterol and carotenoid which share their intermediate pathway from acetyl-CoA to FPP can be used to improve the rate-limiting steps in the carotenogenic pathway. These steps may exist in the steps of mevalonate pathway, especially in the early mevalonate pathway such as the steps catalyzed by HMG-CoA synthase and HMG-CoA reductase. Improved yields of carotenoids, especially astaxanthin, are achievable using the process of the present invention.

In accordance with this invention, the genes and the enzymes involved in the mevalonate pathway from acetyl-CoA to FPP which are biological materials useful in improving the astaxanthin production process are provided. In the present invention, cloning and determination of the genes which code for HMG-CoA synthase, HMG-CoA reductase, mevalonate kinase, mevalonate pyrophosphate decarboxylase and FPP synthase is provided.

This invention also relates to the characterization of such enzymes as a result of the expression of such genes in suitable host organisms such as E. coli. These genes may be amplified in a suitable host, such as P. rhodozyma. The effects on carotenogenesis by these enzymes can be confirmed by cultivation of such a transformant in an appropriate medium under appropriate cultivation conditions.

In one embodiment, there is provided an isolated DNA sequence coding for at least one enzyme involved in the mevalonate pathway or the reaction pathway from isopentenyl pyrophosphate to farnesyl pyrophosphate. More specifically, such enzymes in accordance with the present invention are those having, for example, the following activities: 3-hydroxy-3-methylglutaryl-CoA synthase activity, 3-hydroxy-3-methylglutaryl-CoA reductase activity, mevalonate kinase activity, mevalonate pyrophosphate decarboxylase activity and farnesyl pyrophosphate synthase.

The isolated DNA sequences according to the present invention are more specifically characterized in that (a) they code for enzymes having amino acid sequences as set forth in SEQ ID NOs: 6, 7, 8, 9 and 10. The DNA sequences may alternatively (b) code for variants of such enzymes selected from (i) allelic variants and (ii) enzymes having one or more amino acid addition, insertion, deletion and/or substitution and having the stated enzyme activity.

Preferably, the isolated DNA sequence defined above is derived from a gene of Phaffia rhodozyma. Such a DNA sequence is represented in SEQ ID NOs: 1, 2, 4 and 5. This DNA sequence may also be an isocoding or an allelic variant for the DNA sequence represented in SEQ ID NOs: 1, 2, 4 and 5. In addition, this DNA sequence can be a derivative of a DNA sequence represented in SEQ ID NOs: 1, 2, 4 and 5 with addition, insertion, deletion and/or substitution of one or more nucleotide(s), and coding for a polypeptide having the above-referenced enzyme activity.

In the present invention, such derivatives can be made by recombinant means using one of the DNA sequences as disclosed herein by methods known in the art and disclosed, e.g. by Sambrook et al. (Molecular Cloning, Cold Spring Harbor Laboratory Press, New York, USA, second edition 1989) which is hereby incorporated by reference. Amino acid exchanges in proteins and peptides which do not generally alter the activity of the protein or peptide are known in the art and are described, for example, by H. Neurath and R. L. Hill in The Proteins (Academic Press, New York, 1979, see especially FIG. 6, page 14). The most commonly occurring exchanges are: Ala/Ser, Val/Ile, Asp/Glu, Thr/Ser, Ala/Gly, Ala/Thr, Ser/Asn, Ala/Val, Ser/Gly, Tyr/Phe, Ala/Pro, Lys/Arg, Asp/Asn, Leu/Ile, Leu/Val, Ala/Glu, Asp/Gly, as well as these in reverse.

The present invention also provides an isolated DNA sequence coding for a polypeptide having mevalonate kinase activity, which DNA is selected from (i) a DNA sequence represented in SEQ ID NO: 3; (ii) an isocoding or an allelic variant for the DNA sequence represented in SEQ ID NO: 3; and (iii) a derivative of a DNA sequence represented in SEQ ID NO: 3 with addition, insertion, deletion and/or substitution of one or more nucleotide(s).

The present invention is intended to include those DNA sequences as specified above and as disclosed in the sequence listing, as well as their complementary strands, DNA sequences which include these sequences, DNA sequences which hybridize under standard conditions with such sequences or fragments thereof and DNA sequences, which because of the degeneracy of the genetic code, do not hybridize under standard conditions with such sequences, but which code for polypeptides having exactly the same amino acid sequence.

For purposes of the present invention, “standard conditions” for hybridization mean the conditions which are generally used by a one skilled in the art to detect specific hybridization signals and which are described, e.g. by Sambrook et al., supra Preferably, the standard conditions are so called “stringent hybridization” and non-stringent washing conditions, more preferably so called stringent hybridization and stringent washing conditions. The stringency (high vs. low) of a particular hybridization will of course vary depending upon, for example, the salt concentration and temperature of the hybridization and washes, as well as the lengths of the probe and target DNAs. The examples provided herein set forth representative hybridization conditions but are not to be construed as limiting the scope of the invention.

Furthermore, DNA sequences which can be made by the polymerase chain reaction using primers designed on the basis of the DNA sequences disclosed herein by methods known in the art are also included in the present invention. It is understood that the DNA sequences of the present invention may also be made synthetically as described, e.g. in EP 747 483 which is hereby incorporated by reference.

Another embodiment of the present invention is a recombinant DNA, preferably a vector and/or a plasmid including a sequence coding for an enzyme functional in the mevalonate pathway or the reaction pathway from isopentenyl pyrophosphate to farnesyl pyrophosphate. The recombinant DNA vector and/or plasmid of the present invention includes regulatory regions, such as for example, promoters and terminators, as well as open reading frames of above named DNAs.

Another embodiment of the present invention is a process for transforming a host organism with a recombinant DNA, vector or plasmid. The recombinant organism of the present invention overexpresses a DNA sequence encoding an enzyme involved in the mevalonate pathway or the reaction pathway from isopentenyl pyrophosphate to farnesyl pyrophosphate. The host organism transformed with the recombinant DNA is intended to be used for, e.g., producing isoprenoids and carotenoids, in particular astaxanthin. Thus the present invention also includes such recombinant organisms/transformed hosts.

Another embodiment of the present invention is a method for the production of isoprenoids or carotenoids, preferably carotenoids, which includes cultivating recombinant organisms containing a DNA construct coding for such isoprenoids or carotenoids.

Another embodiment of the present invention is a method for producing an enzyme involved in the mevalonate pathway or the reaction pathway from isopentenyl pyrophosphate to farnesyl pyrophosphate. This method includes culturing a recombinant organism as mentioned above, under conditions conducive to the production of the enzyme. The method may also relate to obtaining the purified enzyme itself.

Another embodiment is a process for overexpressing an enzyme in the mevalonate pathway or an enzyme in the pathway for converting isopentenyl pyrophosphate to farnesyl pyrophosphate. This process includes selecting at least one DNA sequence from the group consisting of SEQ ID NOs: 1-5; transforming a host cell culture with at least one of the DNA sequences selected; expressing in the host cell at least one enzyme in the mevalonate pathway or an enzyme in the pathway for converting isopentenyl pyrophosphate to farnesyl pyrophosphate; and recovering the enzyme(s) from the culture.

The present invention will be understood more easily on the basis of the enclosed figures and the more detailed explanations given below.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 depicts a deduced biosynthetic pathway from acetyl-CoA to astaxanthin in P. rhodozyma.

FIG. 2 shows the expression study by using an artificial mvk gene obtained from an artificial nucleotide addition at the amino terminal end of a pseudo-mvk gene from P. rhodozyma. The cells from 50 ml of broth were subjected to 10% sodium dodecyl sulfide-polyacrylamide gel electrophoresis (SDS-PAGE). Lane 1, E. coli (M15 (pREP4) (pQE30) without IPTG); Lane 2, E. coli (M15 (pREP4) (pQE30) with 1 mM IPTG); Lane 3, Molecular weight marker (105 kDa, 82.0 kDa, 49.0 kDa, 33.3 kD and 28.6 kDa, up to down, BIO-RAD); Lane 4, E.coli (M15 (pREP4) (pMK1209 #3334) without IPTG); Lane 5, E.coli (M15 (pREP4) (pMK209 #3334) with 1 mM IPTG).

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides an isolated DNA sequence which codes for enzymes which are involved in a biological pathway that includes the mevalonate pathway or the reaction pathway from isopentenyl pyrophosphate to farnesyl pyrophosphate. The enzymes of the present invention may be exemplified by those involved in the mevalonate pathway or the reaction pathway from isopentenyl pyrophosphate to farnesyl pyrophosphate in Phaffia rhodozyma. These sequences include, for example, 3-hydroxy-3-methylglutaryl-CoA synthase, 3-hydroxy-3-methylglutaryl-CoA reductase, mevalonate kinase, mevalonate pyrophosphate decarboxylase and farnesyl pyrophosphate synthase.

The present invention has utility in the production of the compounds involved in the mevalonate pathway and the carotenogenic pathway and various products derived from such compounds. The compounds involved in the mevalonate pathway are acetoacetyl-CoA, 3-hydroxymethyl-3-glutaryl-CoA, mevalonic acid, mevalonate-phosphate, mevalonate-pyrophosphate and isopentenyl-pyrophosphate. Subsequently, isopentenyl-pyrophosphate is converted to geranylgeranyl-pyrophosphate through geranyl-pyrophosphate and farnesyl-pyrophosphate via the “Isoprene Biosynthesis” reactions as indicated in FIG. 1.

The compounds involved in the carotenogenic pathway are geranylgeranyl-pyrophosphate, phytoene, lycopene, β-carotene and astaxanthin. Among the compounds involved in the above-mentioned biosynthesis, geranyl-pyrophosphate may be utilized for the production of ubiquinone. Farnesyl-pyrophosphate may be utilized for the production of sterols, such as cholesterol and ergosterol. Geranylgeranyl-pyrophosphate is used to produce vitamin K, vitamin E, chlorophyll and the like. Thus, the present invention has particular utility for the biological production of isoprenoids. As used herein, the term “isoprenoids” is intended to mean a series of compounds having an isopentenyl-pyrophosphate as a skeleton unit. Further examples of isoprenoids are vitamin A and vitamin D₃.

For purposes of the present invention, the term “DNA” is intended to mean a cDNA which contains only an open reading frame flanked between the short fragments in its 5′- and 3′-untranslated region and a genomic DNA which also contains its regulatory sequences, such as its promoter and terminator which are necessary for the expression of the gene of interest.

In general, a gene consists of several parts which have different functions from each other. In eukaryotes, genes which encode a corresponding protein are transcribed to premature messenger RNA (pre-mRNA) differing from the genes for ribosomal RNA (rRNA), small nuclear RNA (snRNA) and transfer RNA (tRNA). Although RNA polymerase II (PolII) plays a central role in this transcription event, PolII cannot solely start transcription without a cis element covering an upstream region containing a promoter and an upstream activation sequence (UAS) and a trans-acting protein factor.

At first, a transcription initiation complex which consists of several basic protein components recognizes the promoter sequence in the 5′-adjacent region of the gene to be expressed. In this event, some additional participants are required in the case of the gene which is expressed under some specific regulation, such as a heat shock response, or adaptation to a nutrition starvation, etc. In such a case, a UAS is required to exist in the 5′-untranslated upstream region around the promoter sequence, and some positive or negative regulator proteins recognize and bind to the UAS. The strength of the binding of the transcription initiation complex to the promoter sequence is affected by such a binding of the trans-acting factor around the promoter. This enables regulation of the transcription activity.

After activation of a transcription initiation complex by phosphorylation, a transcription initiation complex initiates transcription from the transcription start site. Some parts of the transcription initiation complex are detached as an elongation complex which continues the transcription from the promoter region to the 3′ direction of the gene (this step is called a promoter clearance event). The elongation complex continues transcription until it reaches a termination sequence that is located in the 3′-adjacent downstream region of the gene. Pre-mRNA thus generated is modified in the nucleus by the addition of a cap structure at the cap site which substantially corresponds to the transcription start site, and by the addition of polyA stretches at the polyA signal which is located at the 3′-adjacent downstream region. Next, intron structures are removed from the coding region and exon structures are combined to yield an open reading frame whose sequence corresponds to the primary amino acid sequence of a corresponding protein. This modification, in which a mature mRNA is generated, is necessary for stable gene expression.

As used herein, the term “cDNA” is intended to mean the DNA sequence which is reverse-transcribed from this mature mRNA sequence. It can be synthesized by the reverse transcriptase derived from viral species by using a mature mRNA as a template, experimentally.

To express a gene which was derived from a eukaryote, a procedure in which a cDNA is cloned into an expression vector in, for example, E. coli, is often used as shown in this invention. This procedure is used because intron structure specificity varies among eucaryotic organisms which results in an inability to recognize the intron sequence from that of other species. In fact, a prokaryote has no intron structure in its own genetic background. Even in the yeast, the genetic background is different between ascomycetea to which Saccharomyces cerevisiae belongs and basidiomycetea to which P. rhodozyma belongs. For example, Wery et al. showed that the intron structure of the actin gene from P. rhodozyma cannot be recognized nor spliced by the ascomycetous yeast, Saccharomyces cerevisiae (Yeast, 12, 641-651, 1996).

It has been reported that the intron structures of some genes involve regulation of their gene expressions (Dabeva, M. D. et al., Proc. Natl. Acad. Sci. U.S.A., 83, 5854, 1986). Therefore, it may be important to use a genomic fragment which still contains its introns in the case of self-cloning of a gene of interest whose intron structure involves such a regulation of its own gene expression.

To apply a genetic engineering method for a strain improvement study, it is necessary to study its genetic mechanism during, e.g., transcription and translation. It is also important to determine the genetic sequence of the gene, including for example, its UAS, promoter, intron structure and terminator in order to study the genetic mechanism.

According to this invention, the genes which code for the enzymes in the mevalonate pathway were cloned from genomic DNA of P. rhodozyma. The genomic sequence containing the HMG-CoA synthase (hmc) gene, the HMG-CoA reductase (hmg) gene, the mevalonate kinase (mvk) gene, the mevalonate pyrophosphate decarboxylase (mpd) gene and the FPP synthase (fps) gene including their 5′- and 3′-adjacent regions, as well as their intron structures were determined.

Initially, a partial gene fragment containing a portion of the hmc, hmg, mvk, mpd and fps genes was cloned using a degenerate PCR method. Using this degenerate PCR method, the gene of interest can be cloned which has a high amino acid sequence homology to the known enzyme from other species which has the same or similar function. A degenerate primer, which is used as a primer in degenerate PCR, was designed by reverse translation of the amino acid sequence to the corresponding nucleotides (“degenerated”). In such a degenerate primer, a mixed primer which consists of any of A, C, G or T, or a primer containing inosine at an ambiguous codon is generally used. In this invention, mixed primers were used as degenerate primers to clone the genes set forth above. In the present invention, the PCR conditions used can be varied depending on the primers used and genes cloned as described hereinafter.

An entire gene containing its coding region with its intron, as well as its regulation region, such as a promoter or a terminator can be cloned from a chromosome by screening a genomic library which is constructed in a vector such as a phage vector or a plasmid vector in an appropriate host cell using as a labeled probe a partial DNA fragment obtained by degenerate PCR as described above. In the present invention, a host strain such as E. coli, and a vector such as an E. coli vector, a phage vector such as a λ phage vector, or a plasmid vector such as a pUC vector are used in the construction of a library and the following genetic manipulations such as a sequencing, a restriction digestion, a ligation and the like are carried out.

In this invention, an EcoRI genomic library of P. rhodozyma was constructed in the derivatives of λ vector, λZAPII and λDASHII depending on the insert size. The insert size, i.e., the length of insert to be cloned, was determined by Southern blot hybridization for each gene before construction of a library. In this invention, the DNA probes were labeled with digoxigenin (DIG), a steroid hapten instead of a conventional ³²P label, using the protocol which was prepared by the supplier (Boehringer-Mannheim).

A genomic library constructed from the chromosome of P. rhodozyma was screened using a DIG-labeled DNA fragment which contained a portion of the gene of interest as a probe. Hybridized plaques were picked up and used for further study. In the case of λDASHII (insert size was from 9 kb to 23 kb), prepared λDNA was digested by the restriction enzyme EcoRI, followed by cloning of the EcoRI insert into a plasmid vector, such as pUC19 or pBluescriptII SK+. When λZAPII was used in the construction of the genomic library, an in vivo excision protocol was conveniently used for the succeeding step of cloning the insert fragment into the plasmid vector using a derivative of a single stranded M13 phage, Ex assist phage (Stratagene). The plasmid DNA thus obtained was then sequenced.

In this invention, an automated fluorescent DNA sequencer (the ALFred system from Pharmacia) was used with an autocycle sequencing protocol in which the Taq DNA polymerase is employed in most cases of sequencing.

After determining the genomic sequence of each construct, the sequence of the coding region was used for cloning a cDNA of the corresponding gene. The PCR method was also used to clone cDNA fragments. PCR primers whose sequences were identical to the sequence at the 5′- and 3′-end of the open reading frame (ORF) were synthesized with the addition of an appropriate restriction site. Then, PCR was performed using those PCR primers.

In this invention, a cDNA pool was-used as a-template for PCR cloning of the cDNA. The cDNA pool included various cDNA species which were synthesized in vitro by viral reverse transcriptase and Taq polymerase (CapFinder Kit manufactured by Clontech was used) using the MRNA obtained from P. rhodozyma as a template. Using this procedure, a corresponding cDNA was obtained and its identity was confirmed by its sequence. Furthermore, the cDNA was used to confirm its enzyme activity after cloning the cDNA fragment into an expression vector which functions in E. coli, under the strong promoter activity of, for example, the lac or T7 expression system.

Once enzyme activity of the expressed protein is confirmed, the protein is purified and used to raise monoclonal and/or polyclonal antibodies against the purified enzyme according to standard procedures in the art. These antibodies may be used to characterize the expression of the corresponding enzyme in a strain improvement study, an optimization study of the culture condition, and the like. Moreover, these antibodies may be used to purify large quantities of the enzyme in a single step using, for example, an affinity column.

In the present invention, after the rate-limiting step is determined in the biosynthetic pathway which consists of multiple enzymatic reactions, three strategies can be used to enhance the enzymatic activity of the rate-limiting reaction using its genomic sequence.

One strategy is to use the gene itself in its native form. The simplest approach is to amplify the genomic sequence including its regulation sequence such as a promoter and a terminator. This is realized by the cloning of the genomic fragment encoding the enzyme of interest into the appropriate vector on which a selectable marker that functions in P. rhodozyma is harbored.

A drug resistance gene which encodes the enzyme that enables the host to survive in the presence of a toxic antibiotic is often used for the selectable marker. The G418 resistance gene harbored in pGB-Ph9 (Wery et al. (Gene, 184, 89-97, 1997)) is an example of a drug resistance gene. A nutrition complementation marker may also be used in the host which has an appropriate auxotrophy marker. The P. rhodozyma ATCC24221 strain which requires cytidine for its growth is one example of an auxotroph. By using CTP synthetase as donor DNA for ATCC24221, a host vector system using a nutrition complementation marker may be established.

In this system, two types of vectors may be used. One of the vectors is an integrated vector which does not have an autonomous replicating sequence. pGB-Ph9 is an example of this type of a vector. Because such a vector does not have an autonomous replicating sequence, it cannot replicate by itself and is present only in an integrated form on the chromosome of the host as a result of a single-crossing recombination using the homologous sequence between the vector and the chromosome. In case of increasing a dose of the integrated gene on the chromosome, amplification of the gene is often employed using a drug resistance marker. By increasing the concentration of the corresponding drug in the selection medium, only the strain which contains the integrated gene will survive. Using such a selection method, a strain containing the amplified gene may be selected.

Another type of vector is a replicable vector which has an autonomous replicating sequence. Such a vector can exist in a multicopy state which in turn allows the harbored gene to also exist in a multicopy state. By using such a strategy, an enzyme of interest which is coded by the amplified gene can be overexpressed.

Another strategy to overexpress an enzyme of interest is to place the gene of interest under a strong promoter. In such a strategy, the gene does not need to be in present a multicopy state. This strategy is also used to overexpress a gene of interest under the appropriate promoter whose promoter activity is induced in an appropriate growth phase and at an appropriate time during cultivation. For example, production of astaxanthin accelerates in the late phase of growth such as in the case of production of a secondary metabolite. Thus, the expression of carotenogenic genes may be maximized during the late phase of growth. In such a phase, gene expression of most biosynthetic enzymes decreases. Thus, for example, by placing a gene involved in the biosynthesis of a precursor of astaxanthin and whose expression is under the control of a vegetative promoter, such as a gene which encodes an enzyme involved in the mevalonate pathway, downstream of the promoter of the carotenogenic genes, all the genes involved in the biosynthesis of astaxanthin become synchronized in their timing and phase of expression.

Another strategy to overexpress an enzyme of interest is to induce a mutation in its regulatory elements. For this purpose, a kind of reporter gene such as a β-galactosidase gene, a luciferase gene (a gene coding a green fluorescent protein), and the like is inserted between the promoter and the terminator sequence of the gene of interest so that all the parts including promoter, terminator and the reporter gene are fused and function with each other.

For example, transformed P. rhodozyma in which the reporter gene is introduced on the chromosome or on the vector is mutagenized in vivo to induce a mutation within the promoter region of the gene of interest. The mutation is monitored, for example, by detecting a change in activity coded for by the reporter gene. If the mutation occurs in a cis element of the gene, the mutation point would be determined by the rescue of the mutagenized gene and subsequent sequencing. The determined mutation is introduced to the promoter region on the chromosome by recombination between a native promoter sequence and a mutated sequence. In the same procedure, the mutation occurring in the gene which encodes a trans-acting factor can be also obtained. It would also affect the overexpression of the gene of interest.

A mutation may also be induced by in vitro mutagenesis of a cis element in the promoter region. In this approach, a gene cassette, containing a reporter gene fused to a promoter region derived from a gene of interest at its 5′-end and a terminator region from a gene of interest at its 3′-end, is mutagenized and then introduced into P. rhodozyma. By detecting the difference in the activity of the reporter gene, an effective mutation can be screened and identified. Such a mutation can be introduced in the sequence of the native promoter region on the chromosome by the same methods used for in vivo mutation.

As a donor DNA, a gene which encodes an enzyme of the mevalonate pathway or FPP synthase is introduced alone or co-introduced on a plasmid vector. A coding sequence which is identical to its native sequence, as well as its allelic variant (a sequence which has one or more amino acid additions, deletions and/or substitutions) can be used so long as its corresponding enzyme has the stated enzyme activity. Such a vector is introduced into P. rhodozyma by transformation and a transformant is selected by spreading the transformed cells on an appropriate selection medium such as, for example, YPD agar medium containing genetic in the case of pGB-Ph9 as a vector or a minimal agar medium omitting cytidine when the auxotroph ATCC24221 is used as a recipient.

Such a genetically engineered P. rhodozyma is cultivated in an appropriate medium and evaluated for its production of astaxanthin. A hyper-producer of astaxanthin thus selected may be confirmed in view of the relationship between its productivity and the level of gene or protein expression which is introduced by such a genetic engineering method.

Thus in the present invention, all three strategies may be used to enhance the enzymatic activity of the rate limiting step in the enzymatic pathways set forth above.

The following examples are set forth to illustrate compositions and processes of the present invention. These examples are provided for purposes of illustration only and are not intended to be limiting in any sense.

EXAMPLES

The following materials and methods were employed in the examples described below:

Strains

P. rhodozyma ATCC96594 (This strain was redeposited on Apr. 8, 1998 pursuant to the Budapest Treaty and was assigned accession No. 74438).

E. coli DH5α: F⁻φ80d, lacZΔDM15, Δ(lacZYA-argF)U169, hsd(r_(K) ⁻, m_(K) ⁺), recA1, endA1, deoR, thi-1, supE44, gyrA96, relA1 (Toyobo)

E. coli XL1-Blue MRF′: Δ(mcrA)183, Δ(mcrCB-hsdSMR-mrr)173, endA1⁻, supE44, thi-1, recA1, gyrA96, relA1, lac[F′ proAB, lacI^(q)ZΔM15, Tn10 (tet^(r))] (Stratagene)

E. coli SOLR: e14⁻(mcrA), Δ(mcrCB-hsdSMR-mrr)171, sbcC, recB, recJ, umuC:: Tn5(kan^(r)), uvrC, lac, gyrA96, relA1, thi-1, endA1, Δ^(R), [F′ proAB, lacI^(q)Z ΔM15] Su⁻(nonsuppressing) (Stratagene, Calif., USA)

E. coli XL1 MRA (P2): Δ(mcrA)183, Δ(mcrCB-hsdSMR-mrr)173, endA1, supE44, thi-1, gyrA96, relA1, lac (P2 lysogen) (Stratagene)

E. coli BL21 (DE3) (pLysS): dcm⁻, ompTr_(B) ⁻m_(B) ⁻lon⁻Δ(DE3), pLysS (Stratagene)

E. coli M15 (pREP4) (QIAGEN) (Zamenhof P. J. et al., J. Bacteriol. 110, 171-178, 1972)

E. coli KB822: pcnB80, zad:: Tn10, Δ(lacU169), hsdR17, endA1, thi-1, supE44

E. coli TOP10: F⁻, mcrA, Δ(mrr-hsdRMS-mcrBC), φ80, ΔlacZ M15, ΔlacX74, recA1, deoR, araD139, (ara-leu)7697, galU, galK, rpsL (Str^(r)), endA1, nupG (Invitrogen)

Vectors

λZAPII (Stratagene)

λDASHII (Stratagene)

pBluescriptII SK+(Stratagene)

pUC57 (MBI Fermentas)

pMOSBlue T-vector (Amersham)

pET4c (Stratagene)

pQE30 (QIAGEN)

pCR2.1TOPO (Invitrogen)

Media

P. rhodozyma strain is maintained routinely in YPD medium (DIFCO). E. coli strain is maintained in LB medium (10 g Bacto-trypton, 5 g yeast extract (DIFCO) and 5 g NaCl per liter). NZY medium (5 g NaCl, 2 g MgSO₄—7H₂O, 5 g yeast extract (DIFCO), 10 g NZ amine type A (Sheffield) per liter) is used for phage propagation in a soft agar (0.7% agar (WAKO)). When an agar medium was prepared, 1.5% of agar (WAKO) was supplemented.

Methods

General methods of molecular genetics were practiced according to Molecular Cloning: a Laboratory Manual, 2nd Edition (Cold Spring Harbor Laboratory Press, 1989). Restriction enzymes and T4 DNA ligase were purchased from Takara Shuzo (Japan).

Isolation of chromosomal DNA from P. rhodozyma was performed using a QIAGEN Genomic Kit (QIAGEN) following the protocol supplied by the manufacturer. Mini-preps of plasmid DNA from transformed E. coli were performed with the Automatic DNA isolation system (PI-50, Kurabo, Co. Ltd., Japan). Midi-preps of plasmid DNA from an E. coli transformant were performed using a QIAGEN column (QIAGEN). Isolation of λDNA was performed with the Wizard lambda preps DNA purification system (Promega) following the protocol of the manufacturer. A DNA fragment was isolated and purified from agarose using QIAquick or QIAEX II (QIAGEN). Manipulation of λ phage derivatives was done according to the protocol of the manufacturer (Stratagene).

Isolation of total RNA from P. rhodozyma was performed by the phenol method using Isogen (Nippon Gene, Japan). mRNA was purified from total RNA thus obtained using a mRNA separation kit (Clontech). cDNA was synthesized using a CapFinder cDNA construction kit (Clontech).

In vitro packaging was performed using Gigapack III gold packaging extract (Stratagene).

Polymerase chain reaction (PCR) was performed with a thermal cycler from Perkin Elmer model 2400. Each PCR condition is described in the examples. PCR primers were purchased from a commercial supplier or synthesized with a DNA synthesizer (model 392, Applied Biosystems). Fluorescent DNA primers for DNA sequencing were purchased from Pharmacia. DNA sequencing was performed with the automated fluorescent DNA sequencer (ALFred, Pharmacia).

Competent cells of DH5 were purchased from Toyobo (Japan). Competent cells of M15 (pREP4) were prepared by the CaCl₂ method described by Sambrook et al. (Molecular Cloning: A Laboratory Manual, 2nd Edition, Cold Spring Harbor Laboratory Press, 1989).

Example 1 Isolation of mRNA from P. rhodozyma and Construction of cDNA Library

To construct a cDNA library of P. rhodozyma, total RNA was isolated by phenol extraction right after cell disruption. The mRNA from the P. rhodozyma ATCC96594 strain was purified using a mRNA separation kit (Clontech).

P. rhodozyma cells (ATCC96594 strain) from 10 ml of a two-ay-culture in YPD medium were harvested by centrifugation (1500×g for 10 min.) and washed once with extraction buffer (10 mM Na-citrate/HCl (pH 6.2) containing 0.7 M KCl). After suspending the cells in 2.5 ml of extraction buffer, the cells were disrupted by a French press homogenizer (Ohtake Works Corp., Japan) at 1500 kgf/cm² and immediately mixed with 2× volumes of isogen (Nippon gene) according to the method specified by the manufacturer. In this step, 400 μg of total RNA was recovered.

This total RNA was purified using a mRNA separation kit (Clontech) according to the method specified by the manufacturer. Using this method, 16 μg of mRNA from P. rhodozyma ATCC96594 strain was obtained.

To construct a cDNA library, a CapFinder PCR cDNA construction kit (Clontech) was used according to the method specified by the manufacturer. One μg of purified mRNA was applied for a first strand synthesis followed by PCR amplification. After this PCR amplification, 1 mg of a cDNA pool was obtained.

Example 2 Cloning of the Partial hmc (3-hydroxy-3-methylglutaryl-CoA synthase) Gene from P. rhodozyma

To clone a partial hmc gene from P. rhodozyma, a degenerate PCR method was exploited. Two mixed primers whose nucleotide sequences were designed and synthesized (as shown in TABLE 1) based on the common sequence of known HMG-CoA synthase genes from other species.

TABLE 1 Sequence of primers used in the cloning of the hmc gene Hmgs1 ; GGNAARTAYACNATHGGNYTNGGNCA (sense primer) (SEQ ID NO: 11) Hmgs3 ; TANARNSWNSWNGTRTACATRTTNCC (antisense primer) (SEQ ID NO: 12) (N = A, C, G or T; R = A or G, Y = C or T, H = A, T or C, S = C or G, W = A or T)

After a PCR reaction of 25 cycles at 95° C. for 30 seconds, 50° C. for 30 seconds and 72° C. for 15 seconds using ExTaq (Takara Shuzo) as a DNA polymerase and the cDNA pool obtained in example 1 as a template, the resulting reaction mixture was separated by electrophoresis on an agarose gel. A PCR band that has the desired length was recovered and purified by QIAquick (QIAGEN) according to the method of the manufacturer and then ligated to pMOSBlue T-vector (Amersham). After transformation of competent E. coli DH5α cells with the isolated DNA, 6 white colonies were selected and plasmids were isolated with an Automatic DNA isolation system (Kurabo). As a result of sequencing, it was found that the clone had a sequence whose deduced amino acid sequence was similar to known hmc genes. This isolated cDNA clone was designated as pHMC211 and used for further study.

Example 3 Isolation of Genomic DNA from P. rhodozyma

To isolate a genomic DNA from P. rhodozyma, a QIAGEN genomic kit was used according to the method specified by the manufacturer.

At first, the P. rhodozyma ATCC96594 strain cells from 100 ml of an overnight culture in YPD medium were harvested by centrifugation (1500×g for 10 min.) and washed once with TE buffer (10 mM Tris/HCl (pH 8.0) containing 1 mM EDTA). After suspending the cells in 8 ml of Y1 buffer of the QIAGEN genomic kit, lyticase (SIGMA) was added at the concentration of 2 mg/ml to disrupt the cells by enzymatic degradation. This reaction mixture was incubated for 90 minutes at 30° C. and then proceeded to the next extraction step. Finally, 20 μg of genomic DNA was obtained.

Example 4 Southern Blot Hybridization Using pHMC211 as a Probe

Southern blot hybridization was performed to clone a genomic fragment which contains the hmc gene from P. rhodozyma. Two μg of genomic DNA from example 3 was digested by EcoRI and subjected to agarose gel electrophoresis followed by acidic and alkaline treatment. The denatured DNA was transferred to a nylon membrane (Hybond N+, Amersham) using a transblot (Joto Rika) apparatus for an hour. The DNA which was transferred to the nylon membrane was fixed thereto with heat (80° C., 90 minutes). A probe was prepared by labeling template DNA (EcoRI- and SalI-digested pHMC211) using the DIG multipriming method (Boehringer Mannheim).

Hybridization was performed with the method specified by the manufacturer (Boehringer Mannheim). The hybridization experiment was performed using a commercially available DIG (digoxigenin) labeling kit and luminescent detection kit (Boehringer Mannheim, Mannheim, Germany). Standard hybridization conditions were used as follows: The hybridization solution contained formamide (WAKO) 50% (V/V), blocking reagent (Boehringer Mannheim) 2% (W/V), 5×SSC, N-lauroylsarcosine 0.1% (W/V), and SDS 0.3% (W/V). The hybridization was performed at 42° C. overnight. Washing and luminescent detection was performed according to the protocol supplied by the manufacturer. For example, the following standard post hybridization washing routine may be used: wash the nylon membrane twice for 5 minutes each in 2×SSC and 0.1% SDS at room temperature followed by 2 washes of 15 minutes each in 0.1 SSC and 0.1% SDS at 68° C. under constant agitation. These washing conditions may be varied as is known in the art depending upon the DNA, probe and intended result. In the present example, a hybridized band was visualized in the range from 3.5 to 4.0 kilobases (kb).

Example 5 Cloning of a Genomic Fragment Containing hmc Gene

Four μg of the genomic DNA from Example 3 was digested with EcoRI and subjected to agarose gel electrophoresis. Then, DNAs whose length is within the range from 3.0 to 5.0 kb were recovered using a QIAEX II gel extraction kit (QIAGEN) according to the method specified by the manufacturer. The purified DNA was ligated to 1 μg of EcoRI-digested and CIAP (calf intestine alkaline phosphatase)-treated λZAPII (Stratagene) at 16° C. overnight, and packaged by Gigapack III gold packaging extract (Stratagene). The packaged extract was used to infect an E. coli XL1Blue MRF′ strain and over-laid with NZY medium poured onto LB agar medium. About 6000 plaques were screened using an EcoRI- and SalI-digested pHMC211 fragment as a probe. Two plaques were hybridized to the labeled probe and subjected to the in vivo excision protocol according to the method specified by the manufacturer (Stratagene). It was found that isolated plasmids had the same fragments in the opposite direction to each other based on restriction analysis and sequencing. As a result of sequencing, the obtained EcoRI fragment contained the same nucleotide sequence as that of the pHMC211 clone. One of these plasmids was designated pHMC526 and used for further study. A complete nucleotide sequence was obtained by sequencing deletion derivatives of pHMC526, and sequencing with a primer-walking procedure.

Using these methods, it was determined that the insert fragment of pHMC526 consists of 3,431 nucleotides that contained 10 complete exons and one incomplete exon and 10 introns with about 1 kb of 3′-terminal untranslated region.

Example 6 Cloning of Upstream Region of hmc Gene

Cloning of the 5′-region adjacent to the hmc gene was performed using a Genome Walker Kit (Clontech) because pHMC 526 does not contain its 5′ end of hmc gene. As a first step, the PCR primers whose sequences were shown in Table 2 were synthesized.

TABLE 2 Sequence of primers used in the cloning of the 5′-region adjacent to the hmc gene Hmc21 ; GAAGAACCCCATCAAAAGCCTCGA (primary primer) (SEQ ID NO: 13) Hmc22 ; AAAAGCCTCGAGATCCTTGTGAGCG (nested primer) (SEQ ID NO: 14)

Protocols for the genomic library construction and the PCR conditions were the same as those specified by the manufacturer using the genomic DNA preparation obtained in Example 3 as a PCR template. The PCR fragments that had an EcoRV site at the 5′ end (0.45 kb), and that had a PvuII site at the 5′ end (2.7 kb) were recovered and cloned into pMOSBlue T-vector using E. coli DH5α as a host strain. By sequencing 5 independent clones from both constructs, it was confirmed that the 5′ region adjacent to the hmc gene was cloned and a small part (0.1 kb) of an EcoRI fragment within its 3′ end was found. The clone obtained by the PvuII construct in the above experiment was designated as pHMCPv708 and used for further study.

Next, Southern blot analysis was performed using the method set forth in Example 4. The 5′-region adjacent to the hmc gene contained in the 3 kb EcoRI fragment was determined. After construction of a 2.5 to 3.5 kb EcoRI library in λZAPII, 600 plaques were screened and 6 positive clones were selected. As a result of the sequencing of these 6 clones, it was found that 4 clones within 6 positive, plaques had the same sequence as that of the pHMCPv708. One of those clones was named pHMC723 and was used for further analysis.

The PCR primers whose sequences are set forth in TABLE 3 below were synthesized and used to clone a small (0.1 kb) EcoRI fragment located between the 3.5 kb and 3.0 kb, EcoRI fragments on the chromosome of P. rhodozyma.

TABLE 3 Sequence of primers used in cloning the small EcoRI portion of the hmc gene. Hmc30 ; AGAAGCCAGAAGAGAAAA (sense primer) (SEQ ID NO: 15) Hmc31 ; TCGTCGAGGAAAGTAGAT (antisense primer) (SEQ ID NO: 16)

The PCR conditions used were the same as shown in Example 2. An amplified fragment (0.1 kb in length) was cloned into pMOSBlue T-vector and used to transform E. coli DH5α. Plasmids were prepared from 5 independent white colonies and subjected to sequencing.

Using the sequence information, it was determined that the nucleotide sequence (4.8 kb) contained the hmc gene (SEQ ID NO: 1). The coding region was 2,432 base pairs in length and consisted of 11 exons and 10 introns. Introns were scattered throughout the coding region without 5′ or 3′ bias. It was found also that the open reading frame consists of 467 amino acids (SEQ ID NO: 6) whose sequence is strikingly similar to the known amino acid sequence of HMG-CoA synthase gene from other species (49.6% identity to HMG-CoA synthase from Schizosaccharomyces pombe).

Example 7 Expression of hmc Gene in E. coli and Confirmation of its Enzymatic Activity

The PCR primers whose sequences are set forth in TABLE 4 below were synthesized to clone a cDNA fragment of the hmc gene.

TABLE 4 Sequence of primers used in the cloning of cDNA of hmc gene Hmc25 ; GGTACCATATGTATCCTTCTACTACCGAAC (sense primer) (SEQ ID NO: 17) Hmc26 ; GCATGCGGATCCTCAAGCAGAAGGGACCTG (antisense primer) (SEQ ID NO: 18)

The PCR conditions were as follows; 25 cycles at 95° C. for 30 seconds, 55° C. for 30 seconds and 72° C. for 3 minutes. As a template, 0.1 μg of the cDNA pool obtained in Example 2 was used, and Pfu polymerase was used as a DNA polymerase. An amplified 1.5 kb fragment was recovered and cloned in pT7Blue-3 vector (Novagen) using a perfectly blunt cloning kit (Novagen) according to the protocol specified by the manufacturer.

Six independent clones from white colonies of E. coli DH5α transformants were selected and plasmids were prepared from those transformants. As a result of restriction analysis, 2 clones were selected for further characterization by sequencing. One clone has an amino acid substitution at position 280 (from glycine to alanine) and the other clone has a substitution at position 53 (from alanine to threonine). Alignment of amino acid sequences derived from known hmc genes showed that the alanine and glycine residues at position 280 were observed in all the sequences from other species. This fact suggested that an amino acid substitution at position 280 would not affect its enzymatic activity. This clone (mutant at position 280) was selected and designated pHMC731 for a succeeding expression experiment.

Next, a 1.5 kb fragment obtained by NdeI- and BamHI-digestion of pHMC731 was ligated to pET11c (Stratagene) digested by the same pairs of restriction enzymes, and introduced into E. coli DH5α. As a result of restriction analysis, a plasmid that had a correct structure (pHMC818) was recovered. Then, competent E. coli BL21 (DE3) (pLysS) cells (Stratagene) were transformed with the plasmid (pHMC818), and one clone that had a correct structure was selected for further study.

For an expression study, strain BL21 (DE3) (pLysS) (pHMC818) and a vector control strain BL21 (DE3) (pLysS) (pET11c) were cultivated in 100 ml of LB medium at 37° C. until an OD of 0.8 at 600 nm was reached (about 3 hours) in the presence of 100 μg/ml of ampicillin. Then, the broth was divided into two samples of the same volume, and then 1 mM of isopropyl β-D-thiogalactopyranoside (IPTG) was added to one sample (induced). Cultivation of both samples was continued for another 4 hours at 37° C. Twenty five μl of broth was removed from induced- and uninduced-cultures of the hmc clone and the vector control cultures and subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis. It was confirmed that a protein whose size was similar to the deduced molecular weight based on the nucleotide sequence (50.8 kDa) was expressed only in the case of the clone that was harbored in pHMC818 with the induction.

Cells from 50 ml of broth were harvested by centrifugation (1500×g, 10 minutes), washed once and suspended in 2 ml of hmc buffer (200 mM Tris-HCl (pH 8.2)). The cells were disrupted by a French press homogenizer (Ohtake Works) at 1500 kgf/cm² to yield a crude lysate. After centrifugation of the crude lysate, a supernatant fraction was recovered and used as a crude extract for enzymatic analysis. Only in the case of the lysate from the induced clone (pHMC818), was a white pellet spun down and recovered. An enzyme assay for 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) synthase was performed using the photometric assay according to the method by Stewart et al. (J. Biol. Chem. 241(5), 1212-1221, 1966). In the crude extract, the activity of 3-hydroxy-3-methylglutaryl-CoA synthase was not detected. As a result of SDS-PAGE analysis of the crude extract, an expressed protein band that was observed in expressed broth had disappeared. Subsequently, the white pellet that was recovered from the crude lysate of the induced pHMC818 clone was solubilized with 8 M guanidine-HCl, and then subjected to SDS-PAGE analysis. The expressed protein was recovered in the white pellet. This suggested that the expressed protein forms an inclusion body.

Next, an expression experiment in more mild conditions was conducted. Cells were grown in LB medium at 28° C. and the induction was performed by addition of 0.1 mM of IPTG. Subsequently, incubation was continued for another 3.5 hours at 28° C. and then the cells were harvested. Preparation of the crude extract was the same as the previous protocol. Their results are summarized in TABLE 5. It was shown that HMG-CoA synthase activity was only observed in the induced culture of the recombinant strain harboring the hmc gene. This indicates that the cloned hmc gene encodes HMG-CoA synthase.

TABLE 5 Enzymatic characterization of hmc cDNA clone μ mol of HMG-CoA/ plasmid IPTG minute/mg-protein PHMC818 − 0 + 0.146 PET11c − 0 + 0

Example 8 Cloning of hmg (3-hydroxymethyl-3-glutaryl-CoA reductase) Gene

In this example, the cloning protocol for the hmg gene was substantially the same as the protocol used to clone the hmc gene shown in Examples 2 to 7. At first, the PCR primers whose sequences are shown in TABLE 6 were synthesized based on the common sequences of HMG-CoA reductase genes from other species.

TABLE 6 Sequence of primers used in the cloning of hmg gene Red1 ; GCNTGYTGYGARAAYGTNATHGGNTAYATGCC (sense primer) (SEQ ID NO: 19) Red2 ; ATCCARTTDATNGCNGCNGGYTTYTTRTCNGT (antisense primer) (SEQ ID NO: 20) (N = A, C, G or T; R = A or G, Y = C or T, H = A, T or C, D = A, G or T)

After a PCR reaction of 25 cycles at 95° C. for 30 seconds, 54° C. for 30 seconds and 72° C. for 30 seconds using ExTaq (Takara Shuzo) as a DNA polymerase, the reaction mixture was separated by electrophoresis on an agarose gel. A PCR band that had the desired length was recovered and purified by QIAquick (QIAGEN) according to the manufacturer's method and then ligated into pUC57 vector (MBI Fermentas). After the transformation of competent E. coli DH5α cells with this vector, 7 white colonies were selected and plasmids were isolated from those transformants.

As a result of sequencing, it was found that all the clones had a sequence whose deduced amino acid sequence was similar to known HMG-CoA reductase genes. One of the isolated cDNA clones was designated as pRED1219 and was used for further study.

Next, a genomic fragment containing 5′- and 3′-regions adjacent to the hmg gene was cloned with the Genome Walker kit (Clontech). The 2.5 kb fragment of 5′ adjacent region (pREDPVu1226) and the 4.0 kb fragment of the 3′ adjacent region of the hmg gene (pREDEVd1226) were cloned. Based on the sequence of the insert of pREDPVu1226, PCR primers whose sequences are shown in TABLE 7 were synthesized.

TABLE 7 Sequence of primers used in the cloning of cDNA of hmg gene Red8 ; GGCCATTCCACACTTGATGCTCTGC (antisense primer) (SEQ ID NO: 21) Red9 ; GGCCGATATCTTTATGGTCCT (sense primer) (SEQ ID NO: 22)

Subsequently, a cDNA fragment containing a long portion of the hmg cDNA sequence was cloned by PCR using Red 8 and Red 9 as PCR primers and the cDNA pool prepared in Example 2 as template. The cloned plasmid was designated pRED107. The PCR conditions were as follows; 25 cycles for 30 seconds at 94° C., 30 seconds at 55° C. and 1 minute at 72° C.

A Southern blot hybridization study was performed to clone a genomic sequence which contains the entire hmg gene from P. rhodozyma. A probe was prepared by labeling a template DNA (pRED107) according to the DIG multipriming method. Hybridization was performed with the method specified by the manufacturer. As a result, the labeled probe hybridized to two bands that were 12 kb and 4 kb in length. As a result of sequencing of pREDPVu1226, an EcoRI site was not found in the cloned hmg region. This suggested that another species of hmg gene (that has 4 kb of hybridized EcoRI fragment) existed on the genome of P. rhodozyma as found in other organisms.

Next, a genomic library consisting of 9 to 23 kb of an EcoRI fragment in the λDASHII vector was constructed. The packaged extract was used to infect E. coli XL1 Blue, MRA(P2) strain (Stratagene) and over-laid with NZY medium poured onto LB agar medium. About 5000 plaques were screened using the 0.6 kb fragment of StuI-digested pRED107 as a probe. 4 plaques were hybridized to the labeled probe. Then, a phage lysate was prepared and DNA was purified with the Wizard lambda purification system according to the method specified by the manufacturer (Promega). The purified DNA was digested with EcoRI to isolate a 10 kb EcoRI fragment which was cloned into an EcoRI-digested and CIAP-treated pBluescriptII KS-(Stratagene). Eleven white colonies were selected and subjected to a colony PCR using Red9 and −40 universal primer (Pharmacia).

Template DNA for a colony PCR was prepared by heating a cell suspension in which a picked-up colony was suspended in 10 μl of sterilized water for 5 minutes at 99° C. prior to a PCR reaction (PCR conditions; 25 cycles for 30 seconds at 94° C., 30 seconds at 55° C. and 3 minutes at 72° C.). One colony gave 4 kb of a positive PCR band. This indicated that the clone contained the entire hmg gene. A plasmid from this positive clone was prepared and designated pRED611. Subsequently, deletion derivatives of pRED611 were made for sequencing. By combining the sequence obtained from the deletion mutants with the sequence obtained by a primer-walking procedure, the nucleotide sequence of 7,285 base pairs which contains the hmg gene from P. rhodozyma was determined (SEQ ID NO: 2).

The hmg gene from P. rhodozyma consists of 10 exons and 9 introns. The deduced amino acid sequence of 1,091 amino acids in length (SEQ ID NO: 7) showed an extensive homology to known HMG-CoA reductase (53.0% identity to HMG-CoA reductase from Ustilago maydis).

Example 9 Expression of Carboxyl-terminal Domain of hmg Gene in E. coli

Some species of prokaryotes have soluble HMG-CoA reductases or related proteins (Lam et al., J. Biol. Chem. 267, 5829-5834, 1992). However, in eukaryotes HMG-CoA reductase is tethered to the endoplasmic reticulum via an amino-terminal membrane domain (Skalnik et al., J. Biol. Chem. 263, 6836-6841, 1988). In fungi (i.e., Saccharomyces cerevisiae and the smut fungus, Ustilago maydis) and in animals, the membrane domain is large and complex, containing seven or eight transmembrane segments (Croxen et al. Microbiol. 140, 2363-2370, 1994). In contrast, the membrane domains of plant HMG-CoA reductase proteins have only one or two transmembrane segments (Nelson et al. Plant Mol. Biol. 25, 401412, 1994). Despite the difference in the structure and sequence of the transmembrane domain, the amino acid sequences of the catalytic domain are conserved across eukaryotes, archaebacteria and eubacteria

Croxen et al. showed that the C-terminal domain of HMG-CoA reductase derived from the maize fungal pathogen, Ustilago maydis was expressed in active form in E. coli (Microbiology, 140, 2363-2370, 1994). The inventors of the present invention tried to express a C-terminal domain of HMG-CoA reductase from P. rhodozyma in E. coli to confirm its enzymatic activity.

At first, the PCR primers whose sequences were shown in TABLE 8 were synthesized to clone a partial cDNA fragment of the hmg gene. The sense primer sequence corresponds to the sequence which starts from the 597th amino acid (glutamate) residue. The length of the protein and cDNA which was expected to be obtained was 496 amino acids and 1.5 kb, respectively.

TABLE 8 Sequence of primers used in the cloning of a partial cDNA of hmg gene Red54 ; GGTACCGAAGAAATTATGAAGAGTGG (sense primer) (SEQ ID NO: 23) Red55 ; CTGCAGTCAGGCATCCACGTTCACAC (antisense primer) (SEQ ID NO: 24)

The PCR conditions were as follows; 25 cycles at 95° C. for 30 seconds, 55° C. for 30 seconds and 72° C. for 3 minutes. As a template, 0.1 μg of the cDNA pool obtained in Example 2 and as a DNA polymerase, ExTaq polymerase were used. An amplified 1.5 kb fragment was recovered and cloned in pMOSBlue T-vector (Novagen). Twelve independent clones from white colonies of E. coli DH5∀ transformants were selected and plasmids were prepared from those transformants. As a result of restriction analysis, all the clones were selected for further characterization by sequencing. One clone did not have a single amino acid substitution throughout the coding sequence and was designated pRED908.

Next, a 1.5 kb fragment obtained by KpnI- and PstI-digestion of pRED908 was ligated to pQE30 (QIAGEN), digested by the same pairs of restriction enzymes, and transformed to E. coli KB822. As a result of the restriction analysis, a plasmid that had a correct structure (pRED1002) was recovered. Then, competent E. coli M15 (pREP4) cells (QIAGEN) were transformed and one clone that had a correct structure was selected for further study.

For an expression study, strain M15 (pREP4) (pRED1002) and vector control strain M15 (pREP4) (pQE30) were cultivated in 100 ml of LB medium at 30° C. until the OD at 600 nm reached 0.8 (about 5 hours) in the presence of 25 μg/ml of kanamycin and 100 μg/ml of ampicillin. Then, the broth was divided into two samples of the same volume, and 1 mM of IPTG was added to one sample (induced). Cultivation of both samples. continued for another 3.5 hours at 30° C. Twenty five μl of the broth was removed from induced- and uninduced-cultures of the hmg clone and vector control cultures and subjected to SDS-PAGE analysis. It was confirmed that the protein whose size was similar to the deduced molecular weight based on the nucleotide sequence (52.4 kDa) was expressed only in the case of the clone that harbored pRED1002 with the induction.

Cells from 50 ml of broth were harvested by centrifugation (1500×g, 10 minutes), washed once and suspended in 2 ml of hmg buffer (100 mM potassium phosphate buffer (pH 7.0) containing 1 mM of EDTA and 10 mM of dithiothreitol). Cells were disrupted by a French press (Ohtake Works) at 1500 kgf/cm² to yield a crude lysate. After centrifugation of the crude lysate, a supernatant fraction was recovered and used as a crude extract for enzymatic analysis. Only in the case of the induced lysate of the pRED1002 clone, a white pellet was spun down and recovered. An enzyme assay for 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase was performed by the photometric assay according to the method by Servouse et al. (Biochem. J. 240, 541-547, 1986). In the crude extract, the activity of 3-hydroxy-3-methylglutaryl-CoA synthase was not detected. As a result of SDS-PAGE analysis for the crude extract, the expressed protein band that was present in the expressed broth was not observed. Next, the white pellet recovered from the crude lysate of induced pRED1002 clone was solubilized with an equal volume of 20% SDS, and then subjected to SDS-PAGE analysis. An expressed protein was recovered in the white pellet, which indicators that the expressed protein would form an inclusion body.

Next, the expression experiment was performed in more mild conditions. Cells were grown in LB medium at 28° C. and the induction was performed by the addition of 0.1 mM of IPTG. Then, incubation was continued for another 3.5 hours at 28° C. and then the cells were harvested. Preparation of the crude extract was the same as the previous protocol. Results are summarized in TABLE 9. It was shown that 30 times higher induction was observed, and this suggested that the cloned hmg gene codes HMG-CoA reductase.

TABLE 9 Enzymatic characterization of hmg cDNA clone Plasmid IPTG μ mol of NADPH/minute/mg-protein PRED1002 − 0.002 + 0.059 pQE30 − 0 + 0

Example 10 Cloning of Mevalonate Kinase (mvk) Gene

The cloning protocol for the mvk gene used in this example was substantially the same as the protocol for the hmc gene shown in Examples 2 to 7. At first, PCR primers whose sequence are shown in TABLE 10, were synthesized based on the common sequences of the mevalonate kinase genes from other species.

TABLE 10 Sequence of primers used in the cloning of mvk gene Mk1 ; GCNCCNGGNAARGTNATHYTNTTYGGNGA (sense primer) (SEQ ID NO: 25) Mk2 ; CCCCANGTNSWNACNGCRTTRTCNACNCC (antisense primer) (SEQ ID NO: 26) (N = A, C, G or T; R = A or G, Y = C or T, H = A, T or C, S = C or G, W = A or T)

After a PCR reaction of 25 cycles at 95° C. for 30 seconds, 46° C. for 30 seconds and 72° C. for 15 seconds using ExTaq as a DNA polymerase, the reaction mixture was separated by electrophoresis on an agarose gel. A 0.6 kb PCR band whose length was expected to contain a partial mvk gene was recovered and purified by QIAquick according to the method indicated by the manufacturer and. then ligated to pMOSBlue T-vector. After transformation of competent E. coli DH5∀ cells with this construct, 4 white colonies were selected and plasmids were isolated. As a result of sequencing, it was found that one of the clones had a sequence whose deduced amino acid sequence was similar to known mevalonate kinase genes. This cDNA clone was named as pMKI28 and was used for further study.

Next, a partial genomic clone which contained the mvk gene was cloned by PCR. The PCR primers whose sequences are shown in TABLE 11, were synthesized based on the internal sequence of pM128.

TABLE 11 Sequence of primers used in the cloning of genomic DNA containing mvk gene Mk5 ; ACATGCTGTAGTCCATG (sense primer) (SEQ ID NO: 27) Mk6 ; ACTCGGATTCCATGGA (antisense primer) (SEQ ID NO: 28)

The PCR conditions were 25 cycles for 30 seconds at 94° C., 30 seconds at 55° C. and 1 minute at 72° C. The amplified 1.4 kb fragment was cloned into pMOSBlue T-vector. As a result of sequencing, it was confirmed that a genomic fragment containing the mvk gene which had typical intron structures could be obtained and this genomic clone was designated pMK224.

A Southern blot hybridization study was performed to clone a genomic fragment which contained an entire mvk gene from P. rhodozyma. A probe was prepared by labeling a template DNA, pMK224 digested by NcoI with the DIG multipriming method. Hybridization was performed with the method specified by the manufacturer. As a result, the labeled probe hybridized to a 6.5 kb band.

Next, a genomic library consisting of a 5 to 7 kb EcoRI fragment was constructed in the 8ZAPII vector. The packaged extract was used to infect E. coli XL1Blue, MRF′ strain (Stratagene) and over-laid with NZY medium poured onto LB agar medium. About 5000 plaques were screened using a 0.8 kb NcoI-fragment digested from pMK224 as a probe. Seven plaques were hybridized to the labeled probe. Then a phage lysate was prepared according to the method specified by the manufacturer (Stratagene) and in vivo excision was performed using E. coli XL1Blue MRF′ and SOLR strains. Fourteen white colonies were selected and plasmids were isolated from those selected transformants. Then, isolated plasmids were digested by NcoI and subjected to Southern blot hybridization with the same probe as the plaque hybridization. The insert fragments of all the plasmids hybridized to the probe. This indicated that a genomic fragment containing the mvk gene could be cloned. A plasmid from one of the positive clones was prepared and designated as pMK701. About 3 kb of sequence was determined by the primer walking procedure and it was revealed that the 5′ end of the mvk gene was not contained in pMK701.

Next, a PCR primer was synthesized which had the following sequence;

TTGTTGTCGTAGCAGTGGGTGAGAG  (SEQ ID NO: 29).

This primer was used to clone the 5′-adjacent genomnic region of the mvk gene with the Genome Walker Kit according to the method specified by the manufacturer (Clontech). A specific 1.4 kb PCR band was amplified and cloned into pMOSBlue T-vector. All of the transformants of DH5∀ selected had the expected length of the insert. Subsequent sequencing revealed that the 5′-adjacent region of the mvk gene could be cloned. One of the clones was designated as pMKEVR715 and was used for further study. As a result of Southern blot hybridization using the genomic DNA prepared in example 3, the labeled pMKEVR715 construct hybridized to a 2.7 kb EcoRI band. Then, a genomic library in which EcoRI fragments from 1.4 to 3.0 kb in length were cloned into 8ZAPII was constructed. This genomic library was screened with a 1.0 kb EcoRI fragment from pMKEVR715. Fourteen positive plaques were selected from 5000 plaques and plasmids were prepared from those plaques with the in vivo excision procedure.

The PCR primers whose sequences are shown in TABLE 12, taken from the internal sequence of pMKEVR715 were synthesized to select a positive clone with a colony PCR.

TABLE 12 PCR primers used for colony PCR to clone 5′-adjacent region of mvk gene Mk17 ; GGAAGAGGAAGAGAAAAG (sense primer) (SEQ ID NO: 30) Mk18 ; TTGCCGAACTCAATGTAG (antisense primer) (SEQ ID NO: 31)

PCR conditions were as follows: 25 cycles for 30 seconds at 94° C., 30 seconds at 50° C. and 15 seconds at 72° C. From all the candidates except one clone, the positive 0.5 kb band was yielded. One of the clones was selected and designated pMK723 to determine the sequence of the upstream region of mvk gene. After sequencing the 3′-region of pMK723 and combining it with the sequence of pMK701, the genomic sequence of the 4.8 kb fragment containing the mvk gene was determined.

The mvk gene consists of 4 introns and 5 exons (SEQ ID NO: 3). The deduced amino acid sequence except 4 amino acids at the amino terminal end (SEQ ID NO: 8) showed an extensive homology to known mevalonate kinase (44.3% identity to mevalonate kinase from Rattus norvegicus).

Example 11 Expression of mvk Gene by the Introduction of 1 Base at the Amino Terminal Region

Although the amino acid sequence showed a significant homology to known mevalonate kinase, an appropriate start codon for mvk gene could not be found. This result indicated that the cloned gene might be a pseudogene for mevalonate kinase. To confirm this assumption, PCR primers whose sequences are shown in TABLE 13 were synthesized to introduce an artificial nucleotide which resulted in the generation of an appropriate start codon at the amino terminal end.

TABLE 13 PCR primers used for the introduction of a nucleotide into mvk gene Mk33 ; GGATCCATGAGAGCCCAAAAAGAAGA (sense primer) (SEQ ID NO: 32) Mk34 ; GTCGACTCAAGCAAAAGACCAACGAC (antisense primer) (SEQ ID NO: 33)

The artificial amino terminal sequence thus introduced was as follows; NH2-Met-Arg-Ala-Gln. After the PCR reaction of 25 cycles at 95° C. for 30 seconds, 55° C. for 30 seconds and 72° C. for 30 seconds using ExTaq polymerase as a DNA polymerase, the reaction mixture was subjected to agarose gel electrophoresis. An expected 1.4 kb PCR band was amplified and cloned into the pCR2.1 TOPO vector. After transformation of competent E. coli TOP10 cells, 6 white colonies were selected and plasmids were isolated. As a result of sequencing, it was found that one clone had only one amino acid residue change (Asp to Gly change at 81st amino acid residue in SEQ ID NO: 8). This plasmid was named pMK1130 #3334 and used for further study.

Then, the insert fragment of pMK1130 #3334 was cloned into pQE30. This plasmid was named pMK1209 #3334. After transformation of the expression host, M15 (pREP4), an expression study was conducted. The M15 (pREP4) (pMK1209 #3334) strain and vector control strain (M15 (pREP4) (pQE30)) were inoculated into 3 ml of LB medium containing 100 μg/ml of ampicillin. After cultivation at 37° C. for 3.75 hours, the culture broth was divided into two samples. 1 mM IPTG was added to one sample (induced) and incubation of all samples was continued for 3 hours. Cells were harvested from 50 μl of broth by centrifugation and were subjected to SDS-PAGE analysis. A protein which had an expected molecular weight of 48.5 kDa was induced by the addition of IPTG in the culture of M15 (pREP4) (pMK1209 #3334) although no induced protein band was observed in the vector control culture (FIG. 2). This result suggested that the activated form of the mevalonate kinase protein could be expressed by artificial addition of one nucleotide at the amino terminal end.

Example 12 Cloning of the Mevalonate Pyrophosphate Decarboxylase (mpd) Gene

In this example, the cloning protocol for the mpd gene was substantially the same as used to clone the hmc gene shown in Examples 2 to 7. At first, the PCR primers whose sequences are shown in TABLE 14 were synthesized based on the common sequences of the mevalonate pyrophosphate decarboxylase gene from other species.

TABLE 14 Sequence of primers used in the cloning of the mpd gene Mpd1 ; HTNAARTAYTTGGGNAARMGNGA (sense primer) (SEQ ID NO: 34) Mpd2 ; GCRTTNGGNCCNGCRTCRAANGTRTANGC (antisense primer) (SEQ ID NO: 35) (N = A, C, G or T; R = A or G, Y = C or T, H = A, T or C, M = A or C)

After the PCR reaction of 25 cycles at 95° C. for 30 seconds, 50° C. for 30 seconds and 72° C. for 15 seconds using ExTaq as a DNA polymerase, the reaction mixture was subjected to agarose gel electrophoresis. A 0.9 kb PCR band whose length was expected to contain a partial mpd gene was recovered and purified by QIAquick according to the method prepared by the manufacturer and then ligated to pMOSBlue T-vector. After transformation of competent E. coli DH5∀ cells, 6 white colonies were selected and plasmids were isolated therefrom. Two of the 6 clones had the expected insert length. As a result of sequencing, it was found that one of the clones had a sequence whose deduced amino acid sequence was similar to known mevalonate pyrophosphate decarboxylase genes. This cDNA clone was designated pMPD129 and was used for further study.

Next, a partial genomic fragment which contained the mpd gene was cloned by PCR As a result of PCR (whose condition was the same as that of the cloning of a partial cDNA fragment), the amplified 1.05 kb fragment was obtained and was cloned into pMOSBlue T-vector. As a result of sequencing; it was confirmed that a genomic fragment containing the mpd gene which had typical intron structures had been obtained. This genomic clone was designated pMPD220.

A Southern blot hybridization study was performed to clone a genomic fragment which contained the entire mpd gene from P. rhodozyma. The probe was prepared by labeling a template DNA, pMPD220 digested by KpnI, using the DIG multipriming method. Hybridization was performed using the method specified by the manufacturer. As a result, the probe hybridized to a band that was 7.5 kb in length. Next, a genomic library containing a 6.5 to 9.0 kb EcoRI fragment in the 8ZAPII vector was constructed. The packaged extract was used to infect an E. coli XL1Blue, MRF′ strain and was over-laid with NZY medium poured onto LB agar medium. About 6000 plaques were screened using the 0.6 kb fragment of KpnI-digested pMPD220 as a probe. 4 plaques were hybridized to the labeled probe. Then, a phage lysate was prepared according to the method specified by the manufacturer (Stratagene) and an in vivo excision was performed using E. coli XL1Blue MRF′ and SOLR strains. 3 white colonies derived from 4 positive plaques were selected and plasmids were isolated from those selected transformants. Then, the isolated plasmids were subjected to a colony PCR method whose protocol was the same as that in example 8. PCR primers whose sequences are shown in TABLE 14, depending on the sequence found in pMPD129 were synthesized and used for a colony PCR.

TABLE 15 Sequence of primers used in the colony PCR to clone a genomic mpd clone Mpd7 ; CCGAACTCTCGCTCATCGCC (sense primer) (SEQ ID NO: 36) Mpd8 ; CAGATCAGCGCGTGGAGTGA (antisense primer) (SEQ ID NO: 37)

The PCR conditions were substantially the same as used in the cloning of the mvk gene; 25 cycles for 30 seconds at 94° C., 30 seconds at 50° C. and 10 seconds at 72 ° C. All the clones, except one, produced a positive 0.2 kb PCR band. A plasmid was prepared from one of the positive clones and the plasmid was designated pMPD701 and about 3 kb of its sequence was determined by the primer walking procedure (SEQ ID NO: 4). The ORF consisted of 401 amino acids (SEQ ID NO: 9) whose sequence was similar to the sequences of known mevalonate pyrophosphate decarboxylase (52.3% identity to mevalonate pyrophosphate decarboxylase from Schizosaccaromyces pombe). Also determined was a 0.4 kb fragment from the 5′-adjacent region which was expected to include its promoter sequence.

Example 13 Cloning of Farnesyl Pyrophosphate Synthase (fps) Gene

In this example, the cloning protocol for the fps gene was substantially the same as the protocol for cloning the hmc gene shown in Examples 2 to 7. At first, the PCR primers whose sequences are shown in TABLE 16 were synthesized based on the common sequences of the farnesyl pyrophosphate synthase gene from other species.

TABLE 16 Sequence of primers used in the cloning of fps gene Fps1 ; CARGCNTAYTTYYTNGTNGCNGAYGA (sense primer) (SEQ ID NO: 38) Fps2 ; CAYTTRTTRTCYTGDATRTCNGTNCCDATYTT (antisense primer) (SEQ ID NO: 39) (N = A, C, G or T; R = A or G; Y = C or T, D = A, G or T)

After the PCR reaction of 25 cycles at 95° C. for 30 seconds, 54° C. for 30 seconds and 72° C. for 30 seconds using ExTaq as a DNA polymerase, the reaction mixture was subjected to agarose gel electrophoresis. A PCR band that had the desired length (0.5 kb) was recovered and purified by QIAquick according to the method prepared by the manufacturer and then ligated to pUC57 vector. After transformation of competent E. coli DH5∀ cells, 6 white colonies were selected and plasmids were then isolated. One of the plasmids which had the desired length of an insert fragment was sequenced. As a result, it was found that this clone had a sequence whose deduced amino acid sequence was similar to known farnesyl pyrophosphate synthase genes. This cDNA clone was named as pFPS107 and was used for further study.

Next, a genomic fragment was cloned by PCR using the same primer set of Fps1 and Fps2. The same PCR conditions for the cloning of a partial cDNA were used. A 1.0 kb band was obtained which was subsequently cloned and sequenced. This clone contained the same sequence as the pFPS107 and some typical intron fragments. This plasmid was designated pFPS113 and was used for a further experiment.

Then, a 5′- and 3′-adjacent region containing the fps gene was cloned according to the method described in Example 8. At first, the PCR primers whose sequences are shown in TABLE 17 were synthesized.

TABLE 17 Sequences of primers used for a cloning of adjacent region of fps gene Fps7 ; ATCCTCATCCCGATGGGTGAATACT (sense for downstream cloning) (SEQ ID NO: 40) Fps9 ; AGGAGCGGTCAACAGATCGATGAGC (antisense for upstream cloning) (SEQ ID NO: 41)

Amplified PCR bands were isolated and cloned into pMOSBlue T-vector. As a result of sequencing, it was found that the 5′-adjacent region (2.5 kb in length) and the 3′-adjacent region (2.0 kb in length) were cloned. These plasmids were designated pFPSSTu117 and pFPSSTd117, respectively. After sequencing both plasmids, an ORF was found that consisted of 1068 base pairs with 8 introns. The deduced amino acid sequence showed an extensive homology to known farnesyl pyrophosphate synthase from other species. Based on the sequence determined, two PCR primers were synthesized with the sequences shown in TABLE 17 to clone a genomic fps clone and a cDNA clone forks gene expression in E. coli.

TABLE 18 Sequences of primers used for a cDNA and genomic fps cloning Fps27 ; GAATTCATATGTCCACTACGCCTGA (sense primer) (SEQ ID NO: 42) Fps28 ; GTCGACGGTACCTATCACTCCCGCC (antisense primer) (SEQ ID NO: 43)

The PCR conditions were as follows; 25 cycles for 30 seconds at 94° C., 30 seconds at 50° C. and 30 seconds at 72° C. One cDNA clone that had the correct sequence was selected as a result of sequencing analysis of the clones obtained by PCR and was designated pFPS113. Next, a Southern blot hybridization study was performed to clone a genomic fragment which contained the entire fps gene from P. rhodozyma. The probe was prepared by labeling a template DNA, pFPS113 using the DIG multipriming method. As a result, the labeled probe hybridized to a band that was about 10 kb.

Next, a genomic library consisting of 9 to 15 kb of an EcoRI fragment was constructed in a 8DASHII vector. The packaged extract was used to infect E. coli XL1 Blue, MRA(P2) strain (Stratagene) and over-laid with NZY medium poured onto LB agar medium. About 10000 plaques were screened using the 0.6 kb fragment of SacI-digested pFPS113 as a probe. Eight plaques were hybridized to the labeled probe. Then, a phage lysate was prepared according to the method specified by the manufacturer (Promega). All the plaques were subjected to a plaque PCR using Fps27 and Fps28 primers.

Template DNA for a plaque PCR was prepared by heating 2 μl of a solution of phage particles for 5 minutes at 99° C. prior to the PCR reaction. The PCR conditions were the same as that of the pFPS113 cloning hereinbefore. All the plaques gave a 2 kb positive PCR band. This suggested that these clones had an entire region containing the fps gene. One of the 8DNAs that harbored the fps gene was digested with EcoRI to isolate a 10 kb EcoRI fragment which was cloned into an EcoRI-digested and CIAP-treated pBluescriptII KS-(Stratagene).

Twelve white colonies from transformed E. coli DH5∀ cells were selected and plasmids were prepared from these clones and subjected to colony PCR using the same primer sets of Fps27 and Fps28 and the same PCR conditions. A 2 kb positive band was yielded from 3 of 12 candidates. One clone was cloned and designated pFPS603. It was confirmed that the sequence of the fps gene which was previously determined from the sequence of pFPSSTu117 and pFPSStd117 was substantially correct although there were some PCR errors. Finally, the nucleotide sequence was determined of the 4,092 base pairs which contains the fps gene from P. rhodozyma (FIG. 3). An ORF which consisted of 355 amino acids with 8 introns was found (SEQ ID NO: 5). The deduced amino acid sequence (SEQ ID NO: 10) showed an extensive homology to known FPP synthase (65% identity to FPP synthase from Kluyveromyces lactis).

The invention being thus described, it will be seen that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention and all such modifications are intended to be included within the scope of the following claims.

43 1 4775 DNA Phaffia rhodozyma 5′UTR (1239)..(1240) EXPERIMENTAL 1 catcgaagag agcgaagtga ttagggaagc cgaagaggca ctaacaacgt ggttgtatat 60 gtgtgtttat gagtgttata tcgtcaagaa cgaagtccat tcatttagct agacagggag 120 agagggagaa acgtacgggt ttaccctatt ggaccagtct aaagagagaa cgagagtttt 180 tgggtcggtc acctgaagag tttgaacctc cacaagttta ttctagatta tttccggggg 240 tatgtgaagg ataatgtcaa actttgtcca gattgaagaa ggcaagaaag gaaaggggcg 300 aacgagagta tcgtcccatc tatgggtgac cagtcgacct tctgcatcgg cgatcccgag 360 aatggaaggt tccgatggat cagaagtagg tttcctaagc tcaaacatag gtcattgcga 420 gtgagataca tatgcagact gatatgctag tcaaaccgaa cgagatttct ctgtttgctt 480 tcaaaaagac gaaccaacca tttcatgtcc aagatggcag gtccttcgat tctttgaagc 540 tcctccctga tgcggacaga aaagaataaa aagtagacag actgtcaagt cgacagcgca 600 agtttatcaa gctgagcgag aaaactcgaa cttacatacc ttggccgtca gttctgtaga 660 ccaagcatcg gcctttcctc tttgcggcag gtgtacgcgt tggctcacca tcgtcactct 720 cgtctcctga cccgttgctt tccttgacag cagtctgttc cacaggtttc tctaactgat 780 aggtcccaac agcaaagata tctggatgtc tatgtgagaa ctctactgag tcggcagagt 840 acaccgtatc gatataggcg agtgaggaag ctttgaaagg tgaagaagta gcgaaagatc 900 atcagcgaat gaggactatg acaaaaaaga aattttcgta taatccactg gacaaatcac 960 cttccatcgt gtcctccaag agggtttcgt ctgaaacgta aggacgaggt attgatagat 1020 gattgacctt gagtacgcgg atggacaagg aacgagccca ctcccagggc tatgtaacac 1080 cacacgtgac tccacttgaa ttgcggcaga taaacgaagt cttacgatcg gacgactttg 1140 taaccattta gttatttacc cgtcttgttt tcttactttg atcgtcccat tttagacaca 1200 aaaaaagaag ccagaagaga aaagaataaa acgtctaccg tgttctctcc gaattcttac 1260 cacacccaca aaaccataca caatctcaat ctagatatcc agttatgtac acttctacta 1320 ccgaacagcg acccaaagat gttggaattc tcggtatgga ggtatgttgt tcaattctgt 1380 ttgtgttcaa tctttaatca tctttagtcg actgaccggt tcttcctttt tttttcttca 1440 tcaaacaaaa caacccttct cgattcatgt catctttctt tccaatgcgc tactccttct 1500 gtagatctac tttcctcgac gagtgcgtaa ctattctctc ttctgcattc tctctctatt 1560 cccatgttcg atccctcgcc ctcatatggg cgactgtttc atctcttttg cttccgtcca 1620 ttcttctttg atcttgttca ttttctacta atatctcccg acgcgaaata caacactgac 1680 cgcgatttct ctcgatcagg ccatcgctca caaggatctc gaggcttttg atggggttcc 1740 ttccggaaag tacaccatcg gtctcggcaa caacttcatg gccttcaccg acgacactga 1800 ggacatcaac tcgttcgcct tgaacggtca gtctcttccg tttcagcaat cgacaggaaa 1860 aaggcccaag cgcatctcac tgacaccttt ctccgttttg caattccatt tgattgttag 1920 ctgtttccgg tcttctatca aagtacaacg ttgatcccaa gtcaatcggt cgaattgatg 1980 tcggaactga gtccatcatt gacaagtcca aatctgtcaa gacagtcctt atggacttgt 2040 tcgagtccca cggcaacaca gatattgagg gtatcgactc caagaatgcc tgctacggtt 2100 ctaccgcggc cctgttcaat gccgtcaact ggatcgagtc atcctcttgg gacggaagaa 2160 atgccattgt cttctgcgga gacattgcca tctacgccga gggtgctgcc cgacctgccg 2220 gaggtgctgg tgcttgcgcc atcctcatcg gacccgacgc tcccgtcgtc ttcgagcgtg 2280 agttccaatc cgtcattttc ttccacggca gcggctgaaa caacccttat ccgtcattct 2340 catcaatcta gccgtccacg gaaacttcat gaccaacgct tgggacttct acaagcctaa 2400 tctttcttcg tatgttcaaa ttttgaagtt tgcgcttggg agagtcttac actaattcgg 2460 ggtgctcgta tccttcgaat cgtttgttgc tttatagtga atacgttcgt ctgcgcacct 2520 cctatattta gtttttgatc aaatattgtc cattgaatta actctgaaac cttctcctcc 2580 aaatagccca ttgtcgatgg acctctctcc gtcacttcct acgtcaacgc cattgacaag 2640 gcctatgaag cttaccgaac aaagtatgcc aagcgatttg gaggacccaa gactaacggt 2700 gtcaccaacg gacacaccga ggttgccggt gtcagtgctg cgtcgttcga ttaccttttg 2760 ttccacaggt aagcgtcatc ttctgtattc tccttaaatt caaccgatca acggagttaa 2820 ttcgtgtcat catattatct tgttggaaca gtccttacgg aaagcaggtt gtcaaaggcc 2880 acggccgact tgtaagcagt ctttttgtaa ctcttagctt gcagataaaa acttttaggt 2940 ttctggtact cattatttat gcatctcttg aatcacctta tctagttgta caatgacttc 3000 cgaaacaacc ccaacgaccc ggtttttgct gaggtgccag ccgagcttgc tactttggac 3060 atgaagaaaa gtctttcaga caagaatgtc gagaaatctc tgattgctgc ctccaagtct 3120 tctttcaaca agcaggttga gcctggaatg accaccgtcc gacagctcgg aaacttgtac 3180 accgcctctc tcttcggtgc tctcgcaagt ttgttctcta atgttcctgg tgacgagctc 3240 gtaagtcttg atctctatcc caatcatctc ttccttatca attgaactga actcttttct 3300 ttaatgctgg ctttctcttg aacaggtcgg caagcgcatt gctctctacg cctacggatc 3360 tggagctgct gcttctttct atgctcttaa ggtcaagagc tcaaccgctt tcatctctga 3420 gaagcttgat ctcaacaacc gattgagcaa catgaagatt gtcccctgtg atgactttgt 3480 caaagctctg aaggtacgtt ggataatgac tttttttgtg gaccgtggtc tttgtcaacc 3540 gctaacaacc ttcttgaatc ggtctctttt ggtttgaaat tcgctcggcg cttcgacaca 3600 ggtccgagaa gagactcaca acgccgtgtc atattcgccc atcggttcgc ttgacgatct 3660 ctggcctgga tcgtactact tgggagagat tgacagcatg tggcgtcgac agtacaagca 3720 ggtcccttct gcttgaacgg gatattaaaa gtttcaaaag ttatgaaaga ggtcggcgaa 3780 gattcaaaat aaataaatat aacaccttgc tttttggctt gttttccttc ttcactctcg 3840 tttccgatgt gtttcctccg tttcttccct cttttgttcc tttttcctcc ctcttttggt 3900 tacaatctct ttgggtttta caggctggca atctctgtac aatcttcgtt cgcgtgatcc 3960 gacatagata ccgttgtggc atacaccttg cgtcttacat cttttgagag cttcggaggt 4020 gatcttgatg aagaaaattc accattgact cccatctctt gaatgtcctg actaaattga 4080 attggaagca acttatatga agagcaaatt gatggatcca gaaaggaaca agtctagaaa 4140 tcagtgattt gtgcgaaaaa tcagcaaatg ccgcgctgag ccgctcgctg gggagtagac 4200 attgcccatg cgcgtgatgt tgtctgaccg ttctcctcca ttcccccact ctcaaccttc 4260 ctctctttga gaatcgaaga agaaggcgaa gaaaacctga cttgatcctt tacagggtgt 4320 ttcttttgtt cgtatctgag ttacttttcc tcctttcctt cctgcttgag tgaatgactg 4380 atctgactcc tccgcctacc tcggcgactg ggctatatct tgaggataga atatccccct 4440 gacaatccca tttctcaaga ttctttcaaa caagaaaact agttccaatc aatagatcat 4500 ctgatcaacc ttgtgtgaac ataatcatct gcagaagcac tgaactgaga aagtcttcct 4560 cagaggaaag agaatactag ataagatcat tcggttggga aggtaaagga atgaagtctg 4620 gttctgggtt tagctctggt tccgtagggg gttcgactat agtttcttct gttcgactag 4680 aaacaggaga aaccgtacat gtaaatggta tgatattctt gtctctgtat catgtcccgc 4740 tcatctcttt gtttgcaagt cactctggag aattc 4775 2 6370 DNA Phaffia rhodozyma 5′UTR (1043)..(1044) EXPERIMENTAL 2 ggaagacatg atggtgtggg tgtgagtatg agcgtgagcg tgggtatggg cctgggtgtg 60 ggtatgagcg gtggtggtga tggatggatg ggtgggtggc gtggaggggt ccgtgcggca 120 agatgttttc tctgggtagg agcgttctgc attggggcag gagaaaaaat agtgtggtta 180 cgggagatcg tggttacatc aagccatcgt cactgtaagg ctctgtaagg ctcggttgtt 240 aagaaggtaa ccaagtgtaa tcacttggtt cgcggggtga cacttaggct ctggcgatta 300 atatatctga agcagaccaa actattaaca atatactttt ggataagagg tttcaacaag 360 aatctcagct tgaggaaaac tcttatccaa gaaggcgcga gggcgtcccc gttttatatc 420 aggacccctc gcgcatttgg tctgccacta aagatataca tatgacgagc ctagagaggc 480 tcgagatcac gaaaactaaa aagatgaagc atgaaccatg caaactagag catgatggaa 540 aatgggcgaa gaggcataag ggatggaggg aacgaatagc ctgtaggggt aacccacgta 600 agagaacacg tgatacttaa cccgtatccc tgacagtcac ggtgtttctt gagagtcagt 660 aatgtccagc tgtgacctca cgtgactaaa cccgacacgt gtgcttcgac cgaggtggga 720 cgatcttttt tttgggggga gaaaccgagt gggacgatag agaggactac ggagaactgt 780 agtgaattgt agtgcgctca ctacggagag ttctagttga gcaagcgatg tgattttcaa 840 tacaatcccg gactacaagc tctctaatag agctctataa tagaaggaca aaagtcgtcc 900 cactcctatc tcccgcgcgt tttaatagag accgattgtt tttttcccta atgttttatt 960 ttctttcccc gatcggctca tttttcttct ctccgcgtat tcttcacaca acgctccctc 1020 cgatcttttt tcttcttgtt cctgttcctc ttcgtctcct tccattgtct tctttccttc 1080 cttccttcct tcttgcctct agccagcttc aacagcgacg tctctctctc tctgtgtggt 1140 gatctccgac tgtagtgtct ctctcggtca ctttcacgaa tcaacttcgt ttcttttctg 1200 atcgatcggt cgtctttccc tcaatccgtg catacactca cacttacact cacacccaca 1260 cactcaaaca cgctaaataa tcagatccgt ctccccttct tgatctcctt cggcttaggc 1320 aatggcttcc ttgttcggcc tccggcggtc ctcaaacgag cagccgcgct ctcctctgct 1380 catccaatcg aagtcatcct ttctaccttt gtcgtggtca ccttgacgta ctttcagttg 1440 atgtacacca tcaagcacag taatttgtac gtccgatcat ctatttgtcg tgttctcctt 1500 agtctctttc tcttcctcct ttgtctttcg cgtcagcgtg gctggatttc cgtctccatg 1560 tcatttccct tatttcctct tcctgtcatt tgttcctcta cttttctttc tctacctcct 1620 ttccctgtcg tttgctttcc ttcgccagtt gaccaccgat cctcaggatt catggctaac 1680 atgcccaaca caaacttgca tatcatctct cttcgtccac agtctttctc agacgattag 1740 cacacaatct accaccagct gggtcgtcga tgcgttcttc tctttgggat ccagatacct 1800 tgacctcgcg aaggttagtc agttgaccct ctcatgcttc ttttctctca gtcttgtgtg 1860 tgcgcatata cccactcata gacatcttcg tacgctgcac tttccctccc ttagcaagca 1920 gactcggccg atatctttat ggtcctcctc ggttacgtcc ttatgcacgg cacattcgtc 1980 cgactgttcc tcaactttcg tcggatgggc gcaaactttt ggctgccagg catggttctt 2040 gtctcgtcct cctttgcctt cctcaccgcc ctcctcgccg cctcgatcct caacgttccg 2100 atcgacccga tctgtctctc ggaagcactt cccttcctcg tgctcaccgt cggatttgac 2160 aaggacttta ccctcgcaaa atctgtgttc agctccccag aaatcgcacc cgtcatgctt 2220 agacgaaagc cggtgatcca accaggagat gacgacgatc tcgaacagga cgagcacagc 2280 agagtggccg ccaacaaggt tgacattcag tgggcccctc cggtcgccgc ctcccgtatc 2340 gtcattggct cggtcgagaa gatcgggtcc tcgatcgtca gagactttgc cctcgaggtc 2400 gccgtcctcc ttctcggagc cgccagcggg ctcggcggac tcaaggagtt ttgtaagctc 2460 gccgcgttaa ttttggtggc cgactgctgc ttcaccttta ccttctatgt cgccatcctc 2520 accgtcatgg tcgaggtaag ccttttcttc aagtttcttg ctgtcatttt cctttcgaca 2580 cgtatgctca tctttcgttt ccgtctctct cacctttcca ggttcaccga atcaagatca 2640 tccggggctt ccgaccggcc cacaataacc gaacaccgaa tactgtgccc tctaccccta 2700 ctatcgacgg tcaatctacc aacagatccg gcatctcgtc agggcctccg gcccgaccga 2760 ccgtgcccgt gtggaagaaa gtctggagga agctcatggg cccagagatc gattgggcgt 2820 ccgaagctga ggctcgaaac ccggttccaa agttgaagtt gctcttagta agtaaacttc 2880 ctttgttctt ctcatcattc tttatctccg aatcctgacg tcggaccctt ctcgattcaa 2940 agatcttggc ctttcttatc cttcatatcc tcaacctttg cacgcctctg accgagacca 3000 cagctatcaa gcgatcgtct agcatacacc agcccattta tgccgaccct gctcatccga 3060 tcgcacagac aaacacgacg ctccatcggg cgcacagcct agtcatcttt gatcagttcc 3120 ttagtgactg gacgaccatc gtcggagatc caatcatgag caagtggatc atcatcaccc 3180 tgggcgtgtc catcctgctg aacgggttcc tcctaaaagg gatcgcttct ggctctgctc 3240 tcggacccgg tcgtgccgga ggaggaggag ctgccgccgc cgccgccgtc ttgctcggag 3300 cgtgggaaat cgtcgattgg aacaatgaga cagagacctc aacgaacact ccggctggtc 3360 cacccggcca caagaaccag aatgtcaacc tccgactcag tctcgagcgg gatactggtc 3420 tcctccgtta ccagcgtgag caggcctacc aggcccagtc tcagatcctc gctcctattt 3480 caccggtctc tgtcgcgccc gtcgtctcca acggtaacgg taacgcatcg aaatcgattg 3540 agaaaccaat gcctcgtttg gtggtcccta acggaccaag atccttgcct gaatcaccac 3600 cttcgacgac agaatcaacc ccggtcaaca aggttatcat cggtggaccg tccgacaggc 3660 ctgccctaga cggactcgcc aatggaaacg gtgccgtccc ccttgacaaa caaactgtgc 3720 ttggcatgag gtcgatcgaa gaatgcgaag aaattatgaa gagtggtctc gggccttact 3780 cactcaacga cgaagaattg attttgttga ctcaaaaggg aaagattccg ccgtactcgc 3840 tggaaaaagc attgcagaac tgtgagcggg cggtcaagat tcgaagggcg gttatctgta 3900 ggtctttttc tcctttgaat ttcaagcctt ggaggagagg aaagtgcttc ggggtacaat 3960 acaggttgtg caaacaaacc aagagaaact aaagaaaact ttcttctcct ctctctcccc 4020 tcgacgtcag cccgagcatc cgttactaag acgctggaaa cctcggactt gcccatgaag 4080 gattacgact actcgaaagt gatgggcgca tgctgtgaga acgttgtcgg atatatgcct 4140 ctccctgtcg gaatcgctgg tccacttaac attgatggcg aggtcgtccc catcccgatg 4200 gccaccaccg agggaactct cgtggcctcg acgtcgagag gttgcaaagc gctcaacgcg 4260 ggtggcggag tgaccaccgt catcacccag gatgcgatga cgagaggacc ggtggtggat 4320 ttcccttcgg tctctcaggc cgcacaggcc aaacgatggt tggattcggt cgaaggaatg 4380 gaggttatgg ccgcttcgtt caactcgact tctagattcg ccaggttgca gagcatcaag 4440 tgtggaatgg ccggccgatc gctatacatc cgtttggcga ccagtaccgg agatgcgatg 4500 ggaatgaaca tggctggtga gtgcgacgag ttttctttgt tcttcttgtg cggaccatgt 4560 tttctcatcc agccaattca ttcttcattc cttctcggtg tttggcaacc ttttaggtaa 4620 aggaacggag aaagctttgg aaaccctgtc cgagtacttc ccatccatgc agatccttgc 4680 tctttctggt aactactgta tcgacaagaa gccttctgcc atcaactgga ttgagggccg 4740 tggaaagtcc gtggtggccg agtcggtgat ccctggagcg atcgtcaagt ctgtcctcaa 4800 gacaacggtt gcggatctcg tcaacttgaa cattaagaaa aacttgatcg gaagtgccat 4860 ggcaggcagc attggaggat tcaacgccca cgcgtcgaat attttgactg tgcgtacttc 4920 tctttccata ttcgtcctcg tttaatttct tttctgtcca gtcttatgac gtctgattgg 4980 ttcttctttt cacccacaca catacagtca atcttcttgg ctacaggtca ggatcctgca 5040 cagaatgtgg agtcctcaat gtgcatgaca ttgatggagg cgtacgtttt ttgttttgtt 5100 ttccttcttt ttccatatgt ttctacttct actttcttcc cgagtccgcc aagctgatac 5160 ctttatacgg tccttctctt tctcatgacg agtagtgtga acgacggaaa agatctactc 5220 atcacctgct cgatgccggc gatcgagtgc ggaacggtcg gtggaggaac tttcctccct 5280 ccgcaaaacg cctgtttgca gatgctcggt gtcgcaggtg cccatccaga ttcgcccggt 5340 cacaatgctc gtcgactagc aagaatcatc gctgccagtg tgatggctgg agagttgagt 5400 ttgatgagtg ctttggccgc tggtcattta atcaaggccc acatgagtaa gtctgccacc 5460 ttttgataat caaaagggtc gtggtactgg tgtcactgac tggtgactct tcctgtcatg 5520 cagagcacaa tcgatcgaca ccttcgactc ctctaccggt ctcaccgttg gcgacccgac 5580 cgaacacgcc gtcccaccgg tcgattggat tgctcacacc gatgacgtct tccgcatcgg 5640 tcgcctcgat gttctctggg ttcggtagtc cgtcgacgag ctcgctcaag acggtaggta 5700 gcatggcttg cgtcagggaa cgaggggacg agacgagtgt gaacgtggat gcctgaactg 5760 gggactccct tttcttggta tcccttccgt ttttctttcg gcctttgaat cctgtattct 5820 tgtccgtttt ttcatcttct cttcctggtt ctccttctct cgttcatctg caaaaacaaa 5880 attcaatcgc atcggtctct ggcattccat ttgggtttca aaatcaaatc aatctctatc 5940 tactatctca aatatctttt tttcatcttt tgattcattt ctgttgaaaa ctgtcttgcc 6000 cttctcctac ttcttatctc tgccttcttg ccaaagttca attcgttgtc catctgtgca 6060 ctctgatcta tcagtctgta tcaagtacgc tcttaaatct gtaattggct ctcggaggtg 6120 tctcgtcatc tcacatatgg ctggcgatat gatgtgtcgg tttcttcccc tccaacaaag 6180 gcgacgtggc tccttcatca atctttggcg caagctctca aaattctcca aaacggctga 6240 ctaagcaagg tttccaagta ctctcaaacc gagcaaggcc atccatcctc aaatcaactt 6300 gtgaaaccct ttgtggatag accgtccaaa ccgagctctt cccaatcttc gcctcccctt 6360 cttcctgcag 6370 3 4135 DNA Phaffia rhodozyma 5′UTR (911)..(912) EXPERIMENTAL 3 actgactcgg ctaccggaaa atatcttttc aggacgcctt gatcgttttg gacaacacca 60 tgatgtcacc atatcttcag cggccgttgg agctaggagt agacattgta tacgactctg 120 gaacaaagta tttgagtgga caccacgatc tcatggctgg tgtgattact actcgtactg 180 aggagattgg gaaggttcgt gcttgcttgc tttgaatgtc gtgcctaaag ccattgccat 240 aagacagagt ctgatctatg tcgtttgcct acaacagaga atggcctggt tcccaaatgc 300 tatgggaaat gcattgtctc cgttcgactc gttccttctt ctccgaggac tcaaaacact 360 tcctctccga ctggacaagc agcaggcctc atctcacctg atcgcctcgt acttacacac 420 cctcggcttt cttgttcact accccggtct gccttctgac cctgggtacg aacttcataa 480 ctctcaggcg agtggtgcag gtgccgtcat gagctttgag accggagata tcgcgttgag 540 tgaggccatc gtgggcggaa cccgagtttg gggaatcagt gtcagtttcg gagccgtgaa 600 cagtttgatc agcatgcctt gtctaatgag gttagttctt atgccttctt ttcgcgcctt 660 ctaaaatttc tggctgacta attgggtcgg tctttccgtt cttgcatttc agtcacgcat 720 ctattcctgc tcaccttcga gccgagcgag gtctccccga acatctgatt cgactgtgtg 780 tcggtattga ggaccctcac gatttgcttg atgatttgga ggcctctctt gtgaacgctg 840 gcgcaatccg atcagtctct acctcagatt catcccgacc gctcactcct cctgcctctg 900 attctgcctc ggacattcac tccaactggg ccgtcgaccg agccagacag ttcgagcgtg 960 ttaggccttc taactcgaca gccggcgtcg aaggacagct tgccgaactc aatgtagacg 1020 atgcagccag acttgcgggc gatgagagcc aaaaagaaga aattcttgtc agtgcaccgg 1080 gaaaggtcat tctgttcggc gaacatgctg taggccatgg tgttgtgagt gagaaatgaa 1140 agctttatgc tctcattgca tcttaacttt tcctcgcctt ttttgttctc ttcatcccgt 1200 cttgattgta gggatgcccc cctttgcccc tttccccttc ttgcatctgt ctatatttcc 1260 ttatacattt cgctcttaag agcgtctagt tgtaccttat aacaaccttt ggttttagca 1320 tcctttgatt attcatttct ctcatccttc ggtcagaggc tttcggccat ctttacgtct 1380 gattagattg taatagcaag aactatcttg ctaagccttt tctcttcctc ttcctcctat 1440 ataaatcgaa ttcactttcg gacatgttta ttttggggaa atcatcaagg ggtggggggc 1500 caatcccgac actaattttc tgctcacgtc aaaactcagc gttcagaatc agtcactgac 1560 cctgatacgt gtctctatgt gtgtgggtgt acgtgcgaat tgtgactcga cgttctacgc 1620 ttaaaaacag accgggatcg ctgcttccgt tgatcttcga tgctacgctc ttctctcacc 1680 cactgctacg acaacaacat catcgtcgtt atcgtctaca aacattacca tctccctaac 1740 ggacctgaac tttacgcagt cttggcctgt tgattctctt ccttggtcac ttgcgcctga 1800 ctggactgag gcgtctattc cagaatctct ctgcccgaca ttgctcgccg aaatcgaaag 1860 gatcgctggt caaggtggaa acggaggaga aagggagaag gtggcaacca tggcattctt 1920 gtatttgttg gtgctattga gcaaagggaa gccaaggtag gttttttctg tctcttcttt 1980 ttgcctataa agactcttaa ctgacggaga aagtgttggg tttcttcctt cgggggttca 2040 atcaattaaa gtgagccgtt cgagttgacg gctcgatctg cgcttccgat gggagctggt 2100 ctgggttcat ccgccgctct atcgacctct cttgccctag tctttcttct ccacttttct 2160 cacctcagtc caacgacgac tggcagagaa tcaacaatcc cgacggccga cacagaagta 2220 attgacaaat gggcgttctt agctgaaaaa gtcatccatg gaaatccgag tgggattgat 2280 aacgcggtca gtacgagagg aggcgctgtt gctttcaaaa gaaagattga gggaaaacag 2340 gaaggtggaa tggaagcgat caagaggtac gcagacacgg tgcttcatat gccatactcc 2400 agtctgattg acccatgatg aacgtctttc tacatttcga atatagcttc acatccattc 2460 gattcctcat cacagattct cgtatcggaa gggatacaag atctctcgtt gcaggagtga 2520 atgctcgact gattcaggag ccagaggtga tcgtcccttt gttggaagcg attcagcaga 2580 ttgccgatga ggctattcga tgcttgaaag attcagagat ggaacgtgct gtcatgatcg 2640 atcgacttca agttagttct tgttcctttc aagactcttt gtgacattgt gtcttatcca 2700 tttcatcttc ttttttcttc cttcttctgc agaacttggt ctccgagaac cacgcacacc 2760 tagcagcact tggcgtgtcc cacccatccc tcgaagagat tatccggatc ggtgctgata 2820 agcctttcga gcttcgaaca aagttgacag gcgccggtgg aggtggttgc gctgtaaccc 2880 tggtgcccga tggtaaagtc tctccttttc tcttccgtcc aagcgacaca tctgaccgat 2940 gcgcatcctg tacttttggt caaccagact tctcgactga aacccttcaa gctcttatgg 3000 agacgctcgt tcaatcatcg ttcgcccctt atattgcccg agtgggtggt tcaggcgtcg 3060 gattcctttc atcaactaag gccgatccgg aagatgggga gaacagactt aaagatgggc 3120 tggtgggaac ggagattgat gagctagaca gatgggcttt gaaaacgggt cgttggtctt 3180 ttgcttgaac gaaagatagg aaacggtgat tagggtacag atcctttgct gtcattttta 3240 caaaacactt tcttatgtct tcatgactca acgtatgccc tcatctctat ccatagacag 3300 cacggtacct ctcaggtttc aatacgtaag cgttcatcga caaaacatgc ggcacacgaa 3360 aacgagtgga tataagggag aagagagata ttagagcgaa aaagagaaga gtgagagagg 3420 aaaaaaataa ccgagaacaa cttattccgg tttgttagaa tcgaagatcg agaaatatga 3480 agtacatagt ataaagtaaa gaagagaggt ttacctcaga ggtgtgtacg aaggtgagga 3540 caggtaagag gaataattga ctatcgaaaa aagagaactc aacagaagca ctgggataaa 3600 gcctagaatg taagtctcat cggtccgcga tgaaagagaa attgaaggaa gaaaaagccc 3660 ccagtaaaca atccaaccaa cctcttggac gattgcgaaa cacacacacg cacgcggaca 3720 tatttcgtac acaaggacgg gacattcttt ttttatatcc gggtggggag agagagggtt 3780 atagaggatg aatagcaagg ttgatgtttt gtaaaaggtt gcagaaaaag gaaagtgaga 3840 gtaggaacat gcattaaaaa cctgcccaaa gcgatttata tcgttcttct gttttcactt 3900 ctttccgggc gctttcttag accgcggtgg tgaagggtta ctcctgccaa ctagaagaag 3960 caacatgagt caaggattag atcatcacgt gtctcatttg acgggttgaa agatatattt 4020 agatactaac tgcttcccac gccgactgaa aagatgaatt gaatcatgtc gagtggcaac 4080 gaacgaaaga acaaatagta agaatgaatt actagaaaag acagaatgac tagaa 4135 4 2767 DNA Phaffia rhodozyma 5′UTR (372)..(373) EXPERIMENTAL 4 gaattcttcc cgactgggct gatcgacttg actggaagat ctaaggcgga gggatgaagg 60 aagtaattgg agggaatgag gaaaaaaaaa ggcgagggaa cgcggtcttc tttcctggca 120 aggcaatgtc gtgtatctct cttgattctt tcgttgtatc gacggaccac actcttttcg 180 aatgaatatc actatcgcat ccaatgatcg ctatacatgg catttacata tgccagacat 240 cgctgagaaa gagagaacat tcctttggaa aaagcctact gtgcctgaag tcaggctgat 300 gttgattaaa cgtctttccc catcctaagc agacaaacaa cttcttttcg ttcaacacac 360 cacctctctc cgaaaaagct cttcaatcca gtccattaag atggttcata tcgctactgc 420 ctcggctccc gttaacattg cgtgtatcaa ggtccgtctg cattgtgaat gctgctcgtt 480 tgccttgtgt gcgtttggtg gatctgaaag aacccttgct tgaaccattc catctctgct 540 ctttttcttc ctgtcctttc ctttttctca cgacaaaaaa accacctgga ccctttgtgt 600 tcctttccat tggtgttcat acacctaaca cagtactggg gtaaacggga taccaagttg 660 attctcccta caaactcctc cttgtctgtc actctcgacc aggatcacct ccgatcgacg 720 acgtcttctg cttgtgacgc ctcgttcgag aaggatcgac tttggcttaa cgggatcgag 780 gaggaggtca aggctggtgg tcggttggat gtctgcatca aggagatgaa gaagcttcga 840 gcgcaagagg aagagaagga tgccggtctg gagaaagtga gtttttctcc tgtgtgcgtg 900 tgtactctgt ataggtaccg ttgacaggac agtctttctg aagagtttgg atcttactct 960 tttttggggg ggtggtggtg tttgaaataa tgaccaaaat aaagctctca tctttcaacg 1020 tgcaccttgc gtcttacaac aacttcccga ctgccgctgg acttgcttcc tccgcttccg 1080 gtctagctgc gttggtcgcc tcgctcgcct cgctctacaa cctcccaacg aacgcatccg 1140 aactctcgct catcgcccga caaggttctg gttctgcctg ccgatcgctc ttcggcgggt 1200 tcgttgcttg ggaacagggc aagctttcct ctggaaccga ctcgttcgct gttcaggtcg 1260 agcccaggga acactggccc tcactccacg cgctgatctg tgtagtttcc gacgagaaaa 1320 agacgacggc ctcgacggca ggcatgcaaa ccacggtgaa cacctcgcct ttgctccaac 1380 accgaatcga acacgtcgtt ccagcccgga tggaggccat cacccaggcg atccgggcca 1440 aggatttcga ctcgttcgca aagatcacca tgaaggactc caaccagttc cacgccgtct 1500 gcctcgattc ggaacccccg atcttttact tgaacgatgt ctcccgatcg atcatccatc 1560 tcgtcaccga gctcaacaga gtgtccgtcc aggccggcgg tcccgtcctt gccgcctaca 1620 cgttcgacgc cgggccgaac gcggtgatct acgccgagga atcgtccatg ccggagatca 1680 tcaggttaat cgagcggtac ttcccgttgg gaacggcttt cgagaacccg ttcggggtta 1740 acaccgaagg cggtgatgcc ctgagggaag gctttaacca gaacgtcgcc ccggtgttca 1800 ggaagggaag cgtcgcccgg ttgattcaca cccggatcgg tgatggaccc aggacgtatg 1860 gcgaggagga gagcctgatc ggcgaagacg gtctgccaaa ggtcgtcaag gcttagacta 1920 taggttgttt cttctaaatt tgagccttcc tcccgcctcc cttccacaag cataaaacaa 1980 aggataaaca aatgaattat caaaataact ataggttgtt tcttctaaat ttgagccttc 2040 ctcccgcctc ccttccacaa gcataaaaca aaggataaac aaatgaatta tcaaaataaa 2100 ataaaaagtc tgccttcttt gttttggaat acatcttctt tgggacatga cccttctcct 2160 tcttttccgt atacatcttt ttgggtattt catggtgatc aaacaacatt gtgatcgaaa 2220 gcagagacgg ccatggtgct ggctttgagc gtctggcgtt ttgtgtgtcc tgcacttgag 2280 caaccccaag ctgaccgcta ggaaaactca ttgatgtgat ttatatcgta cgatgaaaga 2340 gaataaaatg atagaagaac aaagaagaac aaagtagaag aacgtctgag aagaaagaca 2400 ggaaaatgac acgtacatag tgttcgatga tgaatgatat aatattaaat ataaaatgag 2460 gtaaacgtat agcatcacgg gatgaacgga tgaacatgta gtggacaagg ttgggaaata 2520 ggaatgtaga atccaagaat cgttgactga tggacggacg tatgtaaaca ggtacacccc 2580 aaagaaaaga aagaaagaaa gaaagaaaac acaaagccaa ggaagtaaag cagatggtct 2640 tctaagaata cggcttcaaa aagacagtga acactcgtcg tcgaggaatg acaagaaaag 2700 tgagagacta cgaaaggaag aaaccaagac gaaaagaaga acggagatcg aacggacaga 2760 aataaag 2767 5 4092 DNA Phaffia rhodozyma 5′UTR (787)..(788) EXPERIMENTAL 5 cgcccggtat cttgccacag atgccgccgg agtgtctggc ggagtgctag gaacaacgtc 60 atctccatct gacgagcaag cgtaccacaa gctagctctt cgtctgtcag aaggacatcc 120 acgcaccttc ctggccttcg gggatggcac cttctcgtcg acttcccatg gccgtgcccc 180 tggccttgtg aagatactgt ttgccaagct gagcgcctcc ccgctgctcc aggtccgcaa 240 ggtccgagag tattggacgt cgaagatatg ttcaaagtgt caggcgagtt ctcgggagaa 300 aaaaaaagcg tgggctctga aacagtgtgg aaatgtctac aaagtgagct ggatttattg 360 tgtgtgtatg tgtgtgtgtg tgtatgttct gtgttggttg ctcactgtac tctatgctct 420 ctcttagatt tggggaacag tgctgtgaac gcgtcgcgaa acatgctgca cctagccctt 480 caccagaagg agaaccagag ggcgggaatg ctggtgtctg acgctgctac tgctgctacg 540 ctagccgctg aggctgaggc tggcagaaac taaatccatg acccatcaga tcttggtgat 600 tcgtggtctg aggacaccca agtccaaaag ggctatatat cgaccatcat ccgttgcggt 660 cactcagtag taactaaagc tatacatagg aatgttctga acttgataac cctaacacta 720 cgaaaatatc tcggaaaata gattaatttc cttctcatct caaacaaaag acacaacacc 780 atcaatcacg ctcctttcac acactctcct ttttgctctc tcgttcgaca gaaaataaca 840 tcaatagcca aatgtccact acgcctgaag agaagaaagc agctcgagca aagttcgagg 900 ctgtcttccc ggtcattgcc gatgagattc tcgattatat gaagggtgaa ggcatgcctg 960 ccgaggcttt ggaatggatg aacaaggttc gtcaagggtt tcttctttat tcttctggtc 1020 tttgtttcgg tcgaactggc tttcgaactt ggccttgacc ggttggatct cggttgttgc 1080 gccaaaacga tgtcgaagca aaacttactc ttacctgttc ggtttccttc cttccgacct 1140 tctctctacc cttgcctccg atcggtctta tagaacttgt actacaacac tcccggagga 1200 aaactcaacc gaggactttc cgtggtggat acttatatcc ttctctcgcc ttctggaaaa 1260 gacatctcgg aagaagagta cttgaaggcc gctatcctcg gttggtgtat cgagcttgta 1320 cgcgttttct tcattcacct ttctttctcg tcttctactc tcttctctcg aactatcttc 1380 cctgcgtgtc atcctacacg aatctttata cttacatgtt ggaacatatg ccctgttctt 1440 aattcacctc ttttgtctcg gatggtagct ccaagcttac ttcttggtgg ctgatgatat 1500 gatggacgcc tcaatcaccc gacgaggcca accctgttgg tacaaagttg ttagtccctt 1560 cttctctttc tgtcctcttt cttctgagct atgccaattc ttgattgaaa tcggtggtgc 1620 cgtccggact aatccgtttg tcgtttttat catatcttct tgcacaaaca ggagggagtg 1680 tctaacattg ccatcaacga cgcgttcatg ctcgagggag ctatctactt tttgctcaag 1740 aagcacttcc gaaagcagag ctactatgtc gatctgctag agctcttcca cgatgtttgt 1800 ctctatttct tttcttcctc ccctcaataa actgtatttg tgaccattct ggatcctttc 1860 ctgacgatga atcattcttc ggatgagtag gttactttcc aaaccgagtt gggacagctc 1920 atcgatctgt tgaccgctcc tgaggatcac gtcgatctcg acaagttctc ccttaacaag 1980 tatgcccgtc atatattcgt tttgttgcat tcacgtctga ttgtcagctc cgattattga 2040 ctctgatggt gatggtattg accacatcat gcgatgtttg actttctcgt aggcaccacc 2100 tcatcgttgt ttacaagacc gctttctatt cattctacct tcctgtcgca ctcgctatgc 2160 gaatggtggg tctctctctt caactgttct tcctgatttt cttgaccatc tgtaacataa 2220 atccttggaa ttttgaactc tatgtcatag gtcggcgtga cagatgagga ggcgtacaag 2280 cttgcgctct cgatcctcat cccgatgggt gaatactttc aagttcagga tgatgtgctc 2340 gacgcgttcg ctcctccgga gatccttgga aagatcggaa ccgacatctt ggtgcgtttt 2400 cgttccttcc ttctacgttc tgttttctat cttctgactc cccgtccatc atttatgctt 2460 ctgttaaaac gtattgaaac atcaaaagga caacaaatgt tcatggccta tcaaccttgc 2520 actctctctc gcctcgcccg ctcagcgaga gattctcgat acttcgtacg gtcagaagaa 2580 ctcggaggca gaggccagag tcaaggctct gtacgctgag cttgatatcc agggaaagtt 2640 caacgcttat gagtatgtca tcttttttaa attttctaat tttcttttca tctcttgttc 2700 ccaagaatta ttttgtgaaa gttctgggac tgaacatggt gcatcccttt gggttcactc 2760 cgcatatgtc tcccgtttga ataggcaaca gagttacgag tcgctgaaca agttgattga 2820 cagtattgac gaagagaaga gtggactcaa gaaagaagtc ttccacagct tcctgggtaa 2880 ggtctataag cgaagcaagt aattctcctc tttatatgca aagggaagat tttggcggga 2940 gtgataggta ggaagagaag ggagggtcat attcattagg catttctctt gcagatatag 3000 atgatcaaaa agggatatcg gtcctcttct ttgttccgaa tacataataa gtcatacgaa 3060 gccgaacatg acaaaagtgg ttcatgagat caaacttttt gcatgatctt ctgcgatttt 3120 gtacaattct ctcgcatcct attaggatcg aaccaggaga agatgagaga aggaaaccct 3180 caccccgtca gataacaaac gagaagtctc atcacacaca cacacagatg aaagagaaaa 3240 ataaactgac gaggataact tccaatccga tttttccagc ccacgaacct tccttggtcc 3300 ccgctccggt gccttcgagt ccgatcaatg gggcccaaac gcctgaagat ccaaagaacc 3360 cttgttgagg tgtatttctc gtctgagcaa tcttagatcc ttcaatttgc agtcgcgcat 3420 atataccatc aacatcatcg tcatcaccat cattgtcgtc cacaacagca ccgcaacgcc 3480 gttaatggca gggcttggac aacttgaggc ggtttctagc aggtcggacc gattggagct 3540 cgacccaggg tgcacatcac caagacacat tctccttcaa atgagcgaac aagacataat 3600 gagggaagta gtacgctatc gaacgtcttc tcacatcccg ggttcttggc gtatcttttg 3660 gcgattcttt ttgttgaaat agaaaattga agagaaaaaa agagatccac atgatgaaga 3720 acggctctgt agattcatgc tcgaaagaaa gaaagaaaga aaaagagggg aacgaacgga 3780 tctgaatctg tggccaacca aaaagtaggc acaaagatga caacagcgcc ctcttcgaca 3840 agtctttgaa ctgcttgtgg atgagacaag tcccagcaga tcaacattcc tgctttaccc 3900 catggagtat caaacacctg agaataggtc ttgcccggct gtagataatc tctggaccgt 3960 catatgcgcg aaacgatcag tacgaccgac tctactcgaa gtcgtcaaga gcacggacga 4020 gaacgaaaag aggacaaacc gctctggatg ccataaattt ctcttctcat acctctccca 4080 cccaccctca gg 4092 6 467 PRT Phaffia rhodozyma 6 Met Tyr Thr Ser Thr Thr Glu Gln Arg Pro Lys Asp Val Gly Ile Leu 1 5 10 15 Gly Met Glu Ile Tyr Phe Pro Arg Arg Ala Ile Ala His Lys Asp Leu 20 25 30 Glu Ala Phe Asp Gly Val Pro Ser Gly Lys Tyr Thr Ile Gly Leu Gly 35 40 45 Asn Asn Phe Met Ala Phe Thr Asp Asp Thr Glu Asp Ile Asn Ser Phe 50 55 60 Ala Leu Asn Ala Val Ser Gly Leu Leu Ser Lys Tyr Asn Val Asp Pro 65 70 75 80 Lys Ser Ile Gly Arg Ile Asp Val Gly Thr Glu Ser Ile Ile Asp Lys 85 90 95 Ser Lys Ser Val Lys Thr Val Leu Met Asp Leu Phe Glu Ser His Gly 100 105 110 Asn Thr Asp Ile Glu Gly Ile Asp Ser Lys Asn Ala Cys Tyr Gly Ser 115 120 125 Thr Ala Ala Leu Phe Asn Ala Val Asn Trp Ile Glu Ser Ser Ser Trp 130 135 140 Asp Gly Arg Asn Ala Ile Val Phe Cys Gly Asp Ile Ala Ile Tyr Ala 145 150 155 160 Glu Gly Ala Ala Arg Pro Ala Gly Gly Ala Gly Ala Cys Ala Ile Leu 165 170 175 Ile Gly Pro Asp Ala Pro Val Val Phe Glu Pro Val His Gly Asn Phe 180 185 190 Met Thr Asn Ala Trp Asp Phe Tyr Lys Pro Asn Leu Ser Ser Glu Tyr 195 200 205 Pro Ile Val Asp Gly Pro Leu Ser Val Thr Ser Tyr Val Asn Ala Ile 210 215 220 Asp Lys Ala Tyr Glu Ala Tyr Arg Thr Lys Tyr Ala Lys Arg Phe Gly 225 230 235 240 Gly Pro Lys Thr Asn Gly Val Thr Asn Gly His Thr Glu Val Ala Gly 245 250 255 Val Ser Ala Ala Ser Phe Asp Tyr Leu Leu Phe His Ser Pro Tyr Gly 260 265 270 Lys Gln Val Val Lys Gly His Gly Arg Leu Leu Tyr Asn Asp Phe Arg 275 280 285 Asn Asn Pro Asn Asp Pro Val Phe Ala Glu Val Pro Ala Glu Leu Ala 290 295 300 Thr Leu Asp Met Lys Lys Ser Leu Ser Asp Lys Asn Val Glu Lys Ser 305 310 315 320 Leu Ile Ala Ala Ser Lys Ser Ser Phe Asn Lys Gln Val Glu Pro Gly 325 330 335 Met Thr Thr Val Arg Gln Leu Gly Asn Leu Tyr Thr Ala Ser Leu Phe 340 345 350 Gly Ala Leu Ala Ser Leu Phe Ser Asn Val Pro Gly Asp Glu Leu Val 355 360 365 Gly Lys Arg Ile Ala Leu Tyr Ala Tyr Gly Ser Gly Ala Ala Ala Ser 370 375 380 Phe Tyr Ala Leu Lys Val Lys Ser Ser Thr Ala Phe Ile Ser Glu Lys 385 390 395 400 Leu Asp Leu Asn Asn Arg Leu Ser Asn Met Lys Ile Val Pro Cys Asp 405 410 415 Asp Phe Val Lys Ala Leu Lys Val Arg Glu Glu Thr His Asn Ala Val 420 425 430 Ser Tyr Ser Pro Ile Gly Ser Leu Asp Asp Leu Trp Pro Gly Ser Tyr 435 440 445 Tyr Leu Gly Glu Ile Asp Ser Met Trp Arg Arg Gln Tyr Lys Gln Val 450 455 460 Pro Ser Ala 465 7 1091 PRT Phaffia rhodozyma 7 Met Tyr Thr Ile Lys His Ser Asn Phe Leu Ser Gln Thr Ile Ser Thr 1 5 10 15 Gln Ser Thr Thr Ser Trp Val Val Asp Ala Phe Phe Ser Leu Gly Ser 20 25 30 Arg Tyr Leu Asp Leu Ala Lys Gln Ala Asp Ser Ala Asp Ile Phe Met 35 40 45 Val Leu Leu Gly Tyr Val Leu Met His Gly Thr Phe Val Arg Leu Phe 50 55 60 Leu Asn Phe Arg Arg Met Gly Ala Asn Phe Trp Leu Pro Gly Met Val 65 70 75 80 Leu Val Ser Ser Ser Phe Ala Phe Leu Thr Ala Leu Leu Ala Ala Ser 85 90 95 Ile Leu Asn Val Pro Ile Asp Pro Ile Cys Leu Ser Glu Ala Leu Pro 100 105 110 Phe Leu Val Leu Thr Val Gly Phe Asp Lys Asp Phe Thr Leu Ala Lys 115 120 125 Ser Val Phe Ser Ser Pro Glu Ile Ala Pro Val Met Leu Arg Arg Lys 130 135 140 Pro Val Ile Gln Pro Gly Asp Asp Asp Asp Leu Glu Gln Asp Glu His 145 150 155 160 Ser Arg Val Ala Ala Asn Lys Val Asp Ile Gln Trp Ala Pro Pro Val 165 170 175 Ala Ala Ser Arg Ile Val Ile Gly Ser Val Glu Lys Ile Gly Ser Ser 180 185 190 Ile Val Arg Asp Phe Ala Leu Glu Val Ala Val Leu Leu Leu Gly Ala 195 200 205 Ala Ser Gly Leu Gly Gly Leu Lys Glu Phe Cys Lys Leu Ala Ala Leu 210 215 220 Ile Leu Val Ala Asp Cys Cys Phe Thr Phe Thr Phe Tyr Val Ala Ile 225 230 235 240 Leu Thr Val Met Val Glu Val His Arg Ile Lys Ile Ile Arg Gly Phe 245 250 255 Arg Pro Ala His Asn Asn Arg Thr Pro Asn Thr Val Pro Ser Thr Pro 260 265 270 Thr Ile Asp Gly Gln Ser Thr Asn Arg Ser Gly Ile Ser Ser Gly Pro 275 280 285 Pro Ala Arg Pro Thr Val Pro Val Trp Lys Lys Val Trp Arg Lys Leu 290 295 300 Met Gly Pro Glu Ile Asp Trp Ala Ser Glu Ala Glu Ala Arg Asn Pro 305 310 315 320 Val Pro Lys Leu Lys Leu Leu Leu Ile Leu Ala Phe Leu Ile Leu His 325 330 335 Ile Leu Asn Leu Cys Thr Pro Leu Thr Glu Thr Thr Ala Ile Lys Arg 340 345 350 Ser Ser Ser Ile His Gln Pro Ile Tyr Ala Asp Pro Ala His Pro Ile 355 360 365 Ala Gln Thr Asn Thr Thr Leu His Arg Ala His Ser Leu Val Ile Phe 370 375 380 Asp Gln Phe Leu Ser Asp Trp Thr Thr Ile Val Gly Asp Pro Ile Met 385 390 395 400 Ser Lys Trp Ile Ile Ile Thr Leu Gly Val Ser Ile Leu Leu Asn Gly 405 410 415 Phe Leu Leu Lys Gly Ile Ala Ser Gly Ser Ala Leu Gly Pro Gly Arg 420 425 430 Ala Gly Gly Gly Gly Ala Ala Ala Ala Ala Ala Val Leu Leu Gly Ala 435 440 445 Trp Glu Ile Val Asp Trp Asn Asn Glu Thr Glu Thr Ser Thr Asn Thr 450 455 460 Pro Ala Gly Pro Pro Gly His Lys Asn Gln Asn Val Asn Leu Arg Leu 465 470 475 480 Ser Leu Glu Arg Asp Thr Gly Leu Leu Arg Tyr Gln Arg Glu Gln Ala 485 490 495 Tyr Gln Ala Gln Ser Gln Ile Leu Ala Pro Ile Ser Pro Val Ser Val 500 505 510 Ala Pro Val Val Ser Asn Gly Asn Gly Asn Ala Ser Lys Ser Ile Glu 515 520 525 Lys Pro Met Pro Arg Leu Val Val Pro Asn Gly Pro Arg Ser Leu Pro 530 535 540 Glu Ser Pro Pro Ser Thr Thr Glu Ser Thr Pro Val Asn Lys Val Ile 545 550 555 560 Ile Gly Gly Pro Ser Asp Arg Pro Ala Leu Asp Gly Leu Ala Asn Gly 565 570 575 Asn Gly Ala Val Pro Leu Asp Lys Gln Thr Val Leu Gly Met Arg Ser 580 585 590 Ile Glu Glu Cys Glu Glu Ile Met Lys Ser Gly Leu Gly Pro Tyr Ser 595 600 605 Leu Asn Asp Glu Glu Leu Ile Leu Leu Thr Gln Lys Gly Lys Ile Pro 610 615 620 Pro Tyr Ser Leu Glu Lys Ala Leu Gln Asn Cys Glu Arg Ala Val Lys 625 630 635 640 Ile Arg Arg Ala Val Ile Ser Arg Ala Ser Val Thr Lys Thr Leu Glu 645 650 655 Thr Ser Asp Leu Pro Met Lys Asp Tyr Asp Tyr Ser Lys Val Met Gly 660 665 670 Ala Cys Cys Glu Asn Val Val Gly Tyr Met Pro Leu Pro Val Gly Ile 675 680 685 Ala Gly Pro Leu Asn Ile Asp Gly Glu Val Val Pro Ile Pro Met Ala 690 695 700 Thr Thr Glu Gly Thr Leu Val Ala Ser Thr Ser Arg Gly Cys Lys Ala 705 710 715 720 Leu Asn Ala Gly Gly Gly Val Thr Thr Val Ile Thr Gln Asp Ala Met 725 730 735 Thr Arg Gly Pro Val Val Asp Phe Pro Ser Val Ser Gln Ala Ala Gln 740 745 750 Ala Lys Arg Trp Leu Asp Ser Val Glu Gly Met Glu Val Met Ala Ala 755 760 765 Ser Phe Asn Ser Thr Ser Arg Phe Ala Arg Leu Gln Ser Ile Lys Cys 770 775 780 Gly Met Ala Gly Arg Ser Leu Tyr Ile Arg Leu Ala Thr Ser Thr Gly 785 790 795 800 Asp Ala Met Gly Met Asn Met Ala Gly Lys Gly Thr Glu Lys Ala Leu 805 810 815 Glu Thr Leu Ser Glu Tyr Phe Pro Ser Met Gln Ile Leu Ala Leu Ser 820 825 830 Gly Asn Tyr Cys Ile Asp Lys Lys Pro Ser Ala Ile Asn Trp Ile Glu 835 840 845 Gly Arg Gly Lys Ser Val Val Ala Glu Ser Val Ile Pro Gly Ala Ile 850 855 860 Val Lys Ser Val Leu Lys Thr Thr Val Ala Asp Leu Val Asn Leu Asn 865 870 875 880 Ile Lys Lys Asn Leu Ile Gly Ser Ala Met Ala Gly Ser Ile Gly Gly 885 890 895 Phe Asn Ala His Ala Ser Asp Ile Leu Thr Ser Ile Phe Leu Ala Thr 900 905 910 Gly Gln Asp Pro Ala Gln Asn Val Glu Ser Ser Met Cys Met Thr Leu 915 920 925 Met Glu Ala Val Asn Asp Gly Lys Asp Leu Leu Ile Thr Cys Ser Met 930 935 940 Pro Ala Ile Glu Cys Gly Thr Val Gly Gly Gly Thr Phe Leu Pro Pro 945 950 955 960 Gln Asn Ala Cys Leu Gln Met Leu Gly Val Ala Gly Ala His Pro Asp 965 970 975 Ser Pro Gly His Asn Ala Arg Arg Leu Ala Arg Ile Ile Ala Ala Ser 980 985 990 Val Met Ala Gly Glu Leu Ser Leu Met Ser Ala Leu Ala Ala Gly His 995 1000 1005 Leu Ile Lys Ala His Met Lys His Asn Arg Ser Thr Pro Ser Thr Pro 1010 1015 1020 Leu Pro Val Ser Pro Leu Ala Thr Arg Pro Asn Thr Pro Ser His Arg 1025 1030 1035 1040 Ser Ile Gly Leu Leu Thr Pro Met Thr Ser Ser Ala Ser Val Ala Ser 1045 1050 1055 Met Phe Ser Gly Phe Gly Ser Pro Ser Thr Ser Ser Leu Lys Thr Val 1060 1065 1070 Gly Ser Met Ala Cys Val Arg Glu Arg Gly Asp Glu Thr Ser Val Asn 1075 1080 1085 Val Asp Ala 1090 8 432 PRT Phaffia rhodozyma 8 Lys Glu Glu Ile Leu Val Ser Ala Pro Gly Lys Val Ile Leu Phe Gly 1 5 10 15 Glu His Ala Val Gly His Gly Val Thr Gly Ile Ala Ala Ser Val Asp 20 25 30 Leu Arg Cys Tyr Ala Leu Leu Ser Pro Thr Ala Thr Thr Thr Thr Ser 35 40 45 Ser Ser Leu Ser Ser Thr Asn Ile Thr Ile Ser Leu Thr Asp Leu Asn 50 55 60 Phe Thr Gln Ser Trp Pro Val Asp Ser Leu Pro Trp Ser Leu Ala Pro 65 70 75 80 Asp Trp Thr Glu Ala Ser Ile Pro Glu Ser Leu Cys Pro Thr Leu Leu 85 90 95 Ala Glu Ile Glu Arg Ile Ala Gly Gln Gly Gly Asn Gly Gly Glu Arg 100 105 110 Glu Lys Val Ala Thr Met Ala Phe Leu Tyr Leu Leu Val Leu Leu Ser 115 120 125 Lys Gly Lys Pro Ser Glu Pro Phe Glu Leu Thr Ala Arg Ser Ala Leu 130 135 140 Pro Met Gly Ala Gly Leu Gly Ser Ser Ala Ala Leu Ser Thr Ser Leu 145 150 155 160 Ala Leu Val Phe Leu Leu His Phe Ser His Leu Ser Pro Thr Thr Thr 165 170 175 Gly Arg Glu Ser Thr Ile Pro Thr Ala Asp Thr Glu Val Ile Asp Lys 180 185 190 Trp Ala Phe Leu Ala Glu Lys Val Ile His Gly Asn Pro Ser Gly Ile 195 200 205 Asp Asn Ala Val Ser Thr Arg Gly Gly Ala Val Ala Phe Lys Arg Lys 210 215 220 Ile Glu Gly Lys Gln Glu Gly Gly Met Glu Ala Ile Lys Ser Phe Thr 225 230 235 240 Ser Ile Arg Phe Leu Ile Thr Asp Ser Arg Ile Gly Arg Asp Thr Arg 245 250 255 Ser Leu Val Ala Gly Val Asn Ala Arg Leu Ile Gln Glu Pro Glu Val 260 265 270 Ile Val Pro Leu Leu Glu Ala Ile Gln Gln Ile Ala Asp Glu Ala Ile 275 280 285 Arg Cys Leu Lys Asp Ser Glu Met Glu Arg Ala Val Met Ile Asp Arg 290 295 300 Leu Gln Asn Leu Val Ser Glu Asn His Ala His Leu Ala Ala Leu Gly 305 310 315 320 Val Ser His Pro Ser Leu Glu Glu Ile Ile Arg Ile Gly Ala Asp Lys 325 330 335 Pro Phe Glu Leu Arg Thr Lys Leu Thr Gly Ala Gly Gly Gly Gly Cys 340 345 350 Ala Val Thr Leu Val Pro Asp Asp Phe Ser Thr Glu Thr Leu Gln Ala 355 360 365 Leu Met Glu Thr Leu Val Gln Ser Ser Phe Ala Pro Tyr Ile Ala Arg 370 375 380 Val Gly Gly Ser Gly Val Gly Phe Leu Ser Ser Thr Lys Ala Asp Pro 385 390 395 400 Glu Asp Gly Glu Asn Arg Leu Lys Asp Gly Leu Val Gly Thr Glu Ile 405 410 415 Asp Glu Leu Asp Arg Trp Ala Leu Lys Thr Gly Arg Trp Ser Phe Ala 420 425 430 9 401 PRT Phaffia rhodozyma 9 Met Val His Ile Ala Thr Ala Ser Ala Pro Val Asn Ile Ala Cys Ile 1 5 10 15 Lys Tyr Trp Gly Lys Arg Asp Thr Lys Leu Ile Leu Pro Thr Asn Ser 20 25 30 Ser Leu Ser Val Thr Leu Asp Gln Asp His Leu Arg Ser Thr Thr Ser 35 40 45 Ser Ala Cys Asp Ala Ser Phe Glu Lys Asp Arg Leu Trp Leu Asn Gly 50 55 60 Ile Glu Glu Glu Val Lys Ala Gly Gly Arg Leu Asp Val Cys Ile Lys 65 70 75 80 Glu Met Lys Lys Leu Arg Ala Gln Glu Glu Glu Lys Asp Ala Gly Leu 85 90 95 Glu Lys Leu Ser Ser Phe Asn Val His Leu Ala Ser Tyr Asn Asn Phe 100 105 110 Pro Thr Ala Ala Gly Leu Ala Ser Ser Ala Ser Gly Leu Ala Ala Leu 115 120 125 Val Ala Ser Leu Ala Ser Leu Tyr Asn Leu Pro Thr Asn Ala Ser Glu 130 135 140 Leu Ser Leu Ile Ala Arg Gln Gly Ser Gly Ser Ala Cys Arg Ser Leu 145 150 155 160 Phe Gly Gly Phe Val Ala Trp Glu Gln Gly Lys Leu Ser Ser Gly Thr 165 170 175 Asp Ser Phe Ala Val Gln Val Glu Pro Arg Glu His Trp Pro Ser Leu 180 185 190 His Ala Leu Ile Cys Val Val Ser Asp Glu Lys Lys Thr Thr Ala Ser 195 200 205 Thr Ala Gly Met Gln Thr Thr Val Asn Thr Ser Pro Leu Leu Gln His 210 215 220 Arg Ile Glu His Val Val Pro Ala Arg Met Glu Ala Ile Thr Gln Ala 225 230 235 240 Ile Arg Ala Lys Asp Phe Asp Ser Phe Ala Lys Ile Thr Met Lys Asp 245 250 255 Ser Asn Gln Phe His Ala Val Cys Leu Asp Ser Glu Pro Pro Ile Phe 260 265 270 Tyr Leu Asn Asp Val Ser Arg Ser Ile Ile His Leu Val Thr Glu Leu 275 280 285 Asn Arg Val Ser Val Gln Ala Gly Gly Pro Val Leu Ala Ala Tyr Thr 290 295 300 Phe Asp Ala Gly Pro Asn Ala Val Ile Tyr Ala Glu Glu Ser Ser Met 305 310 315 320 Pro Glu Ile Ile Arg Leu Ile Glu Arg Tyr Phe Pro Leu Gly Thr Ala 325 330 335 Phe Glu Asn Pro Phe Gly Val Asn Thr Glu Gly Gly Asp Ala Leu Arg 340 345 350 Glu Gly Phe Asn Gln Asn Val Ala Pro Val Phe Arg Lys Gly Ser Val 355 360 365 Ala Arg Leu Ile His Thr Arg Ile Gly Asp Gly Pro Arg Thr Tyr Gly 370 375 380 Glu Glu Glu Ser Leu Ile Gly Glu Asp Gly Leu Pro Lys Val Val Lys 385 390 395 400 Ala 10 355 PRT Phaffia rhodozyma 10 Met Ser Thr Thr Pro Glu Glu Lys Lys Ala Ala Arg Ala Lys Phe Glu 1 5 10 15 Ala Val Phe Pro Val Ile Ala Asp Glu Ile Leu Asp Tyr Met Lys Gly 20 25 30 Glu Gly Met Pro Ala Glu Ala Leu Glu Trp Met Asn Lys Asn Leu Tyr 35 40 45 Tyr Asn Thr Pro Gly Gly Lys Leu Asn Arg Gly Leu Ser Val Val Asp 50 55 60 Thr Tyr Ile Leu Leu Ser Pro Ser Gly Lys Asp Ile Ser Glu Glu Glu 65 70 75 80 Tyr Leu Lys Ala Ala Ile Leu Gly Trp Cys Ile Glu Leu Leu Gln Ala 85 90 95 Tyr Phe Leu Val Ala Asp Asp Met Met Asp Ala Ser Ile Thr Arg Arg 100 105 110 Gly Gln Pro Cys Trp Tyr Lys Val Glu Gly Val Ser Asn Ile Ala Ile 115 120 125 Asn Asn Ala Phe Met Leu Glu Gly Ala Ile Tyr Phe Leu Leu Lys Lys 130 135 140 His Phe Arg Lys Gln Ser Tyr Tyr Val Asp Leu Leu Glu Leu Phe His 145 150 155 160 Asp Val Thr Phe Gln Thr Glu Leu Gly Gln Leu Ile Asp Leu Leu Thr 165 170 175 Ala Pro Glu Asp His Val Asp Leu Asp Lys Phe Ser Leu Asn Lys His 180 185 190 His Leu Ile Val Val Tyr Lys Thr Ala Phe Tyr Ser Phe Tyr Leu Pro 195 200 205 Val Ala Leu Ala Met Arg Met Val Gly Val Thr Asp Glu Glu Ala Tyr 210 215 220 Lys Leu Ala Leu Ser Ile Leu Ile Pro Met Gly Glu Tyr Phe Gln Val 225 230 235 240 Gln Asp Asp Val Leu Asp Ala Phe Arg Pro Pro Glu Ile Leu Gly Lys 245 250 255 Ile Gly Thr Asp Ile Leu Asp Asn Lys Cys Ser Trp Pro Ile Asn Leu 260 265 270 Ala Leu Ser Pro Ala Ser Pro Ala Gln Arg Glu Ile Leu Asp Thr Ser 275 280 285 Tyr Gly Gln Lys Asn Ser Glu Ala Glu Ala Arg Val Lys Ala Leu Tyr 290 295 300 Ala Glu Leu Asp Ile Gln Gly Lys Phe Asn Ala Tyr Glu Gln Gln Ser 305 310 315 320 Tyr Glu Ser Leu Asn Lys Leu Ile Asp Ser Ile Asp Glu Glu Lys Ser 325 330 335 Gly Leu Lys Lys Glu Val Phe His Ser Phe Leu Gly Lys Val Tyr Lys 340 345 350 Arg Ser Lys 355 11 26 DNA Artificial Sequence Description of Artificial Sequence Degenerate sense primer for cloning of HMC 11 ggnaartaya cnathggnyt nggnca 26 12 26 DNA Artificial Sequence Description of Artificial Sequence Degenerate antisense primer for cloning of HMC gene 12 tanarnswns wngtrtacat rttncc 26 13 24 DNA Artificial Sequence Description of Artificial Sequence Primary primer for cloning of 5′-adjacent region of HMC gene 13 gaagaacccc atcaaaagcc tcga 24 14 25 DNA Artificial Sequence Description of Artificial Sequence Nested primer for cloning of 5′-adjacent region of HMC gene 14 aaaagcctcg agatccttgt gagcg 25 15 18 DNA Artificial Sequence Description of Artificial Sequence Sense primer for cloning of small EcoRI portion of HMC gene 15 agaagccaga agagaaaa 18 16 18 DNA Artificial Sequence Description of Artificial Sequence Antisense primer for cloning of small EcoRI portion of HMC gene 16 tcgtcgagga aagtagat 18 17 30 DNA Artificial Sequence Description of Artificial Sequence Sense primer for cloning of cDNA of HMC gene 17 ggtaccatat gtatccttct actaccgaac 30 18 30 DNA Artificial Sequence Description of Artificial Sequence Antisense primer for cloning of cDNA of HMC gene 18 gcatgcggat cctcaagcag aagggacctg 30 19 32 DNA Artificial Sequence Description of Artificial Sequence Degenerate sense primer for cloning HMG gene 19 gcntgytgyg araaygtnat hggntayatg cc 32 20 32 DNA Artificial Sequence Description of Artificial Sequence Degenerate antisense primer for cloning of HMG gene 20 atccarttda tngcngcngg yttyttrtcn gt 32 21 25 DNA Artificial Sequence Description of Artificial Sequence Antisense primer for cloning of cDNA of HMG gene 21 ggccattcca cacttgatgc tctgc 25 22 21 DNA Artificial Sequence Description of Artificial Sequence Sense primer for cloning of cDNA of HMG gene 22 ggccgatatc tttatggtcc t 21 23 26 DNA Artificial Sequence Description of Artificial Sequence Sense primer for cloning of cDNA of HMG gene 23 ggtaccgaag aaattatgaa gagtgg 26 24 26 DNA Artificial Sequence Description of Artificial Sequence Antisense primer for cloning of cDNA of HMG gene 24 ctgcagtcag gcatccacgt tcacac 26 25 29 DNA Artificial Sequence Description of Artificial Sequence Degenerate sense primer for cloning of MVK gene 25 gcnccnggna argtnathyt nttyggnga 29 26 29 DNA Artificial Sequence Description of Artificial Sequence Degenerate antisense primer for cloning of MVK gene 26 ccccangtns wnacngcrtt rtcnacncc 29 27 17 DNA Artificial Sequence Description of Artificial Sequence Sense primer for cloning of genomic DNA containing MVK gene 27 acatgctgta gtccatg 17 28 16 DNA Artificial Sequence Description of Artificial Sequence Antisense primer for cloning of genomic DNA containing MVK gene 28 actcggattc catgga 16 29 25 DNA Artificial Sequence Description of Artificial Sequence Primer for genomic walking to clone 5′-adjacent region of MVK gene 29 ttgttgtcgt agcagtgggt gagag 25 30 18 DNA Artificial Sequence Description of Artificial Sequence Sense primer for cloning of 5′-adjacent region of MVK gene 30 ggaagaggaa gagaaaag 18 31 18 DNA Artificial Sequence Description of Artificial Sequence Antisense primer for cloning of 5′-adjacent region of MVK gene 31 ttgccgaact caatgtag 18 32 26 DNA Artificial Sequence Description of Artificial Sequence Sense primer for introduction of a nucleotide into MVK gene 32 ggatccatga gagcccaaaa agaaga 26 33 26 DNA Artificial Sequence Description of Artificial Sequence Antisense primer for introduction of a nucleotide into MVK gene 33 gtcgactcaa gcaaaagacc aacgac 26 34 23 DNA Artificial Sequence Description of Artificial Sequence Degenerate sense primer for cloning of MPD gene 34 htnaartayt tgggnaarmg nga 23 35 29 DNA Artificial Sequence Description of Artificial Sequence Degenerate antisense primer for cloning of MPD gene 35 gcrttnggnc cngcrtcraa ngtrtangc 29 36 20 DNA Artificial Sequence Description of Artificial Sequence Sense primer for colony PCR to clone a genomic MPD clone 36 ccgaactctc gctcatcgcc 20 37 20 DNA Artificial Sequence Description of Artificial Sequence Antisense primer for colony PCR to clone a genomic MPD clone 37 cagatcagcg cgtggagtga 20 38 26 DNA Artificial Sequence Description of Artificial Sequence Degenerate sense primer for cloning of FPS gene 38 cargcntayt tyytngtngc ngayga 26 39 32 DNA Artificial Sequence Description of Artificial Sequence Degenerate antisense primer for cloning of FPS gene 39 cayttrttrt cytgdatrtc ngtnccdaty tt 32 40 25 DNA Artificial Sequence Description of Artificial Sequence Sense primer for cloningof FPS downstream region 40 atcctcatcc cgatgggtga atact 25 41 25 DNA Artificial Sequence Description of Artificial Sequence Antisense primer for cloning of FPS upstream region 41 aggagcggtc aacagatcga tgagc 25 42 25 DNA Artificial Sequence Description of Artificial Sequence Sense primer for cloning of cDNA and genomic FPS gene 42 gaattcatat gtccactacg cctga 25 43 25 DNA Artificial Sequence Description of Artificial Sequence Antisense primer for cloning of cDNA and genomic FPS gene 43 gtcgacggta cctatcactc ccgcc 25 

What is claimed is:
 1. An isolated DNA sequence comprising a DNA sequence that hybridizes to SEQ ID NO:1 under the following conditions: hybridization in 50% formamide (v/v), 2% blocking agent, 5XSSC, 0.1% N-lauroylsarcosine (w/v), and 0.1% SDS at 42° C. overnight followed by two washes for 5 minutes each in 2XSSC and 0.1% SDS at room temperature followed by two additional washes of 15 minutes each in 0.1XSSC and 0.1% SDS at 68° C., wherein the DNA sequence encodes an amino acid sequence having 3-hydroxy-3-methylglutaryl-CoA synthase (HMG-CoA synthase) activity.
 2. An isolated DNA sequence according to claim 1 wherein the DNA sequence encodes the amino acid sequence set forth in SEQ ID NO:6.
 3. An isolated DNA sequence according to claim 1 comprising SEQ ID NO:1.
 4. An isolated DNA sequence according to claim 3 consisting essentially of SEQ ID NO:1.
 5. An isolated DNA sequence according to claim 1 consisting of SEQ ID NO:1 or a fragment thereof, which fragment encodes an amino acid sequence having HMG-CoA synthase activity.
 6. An isolated DNA sequence according to claim 1 wherein the DNA sequence that hybridizes to SEQ ID NO:1 is a derivative of SEQ ID NO:1, which contains an addition, insertion, deletion, and/or substitution of one or more nucleotide(s).
 7. An isolated DNA sequence according claim 1 wherein the DNA sequence is isolated from Phaffia rhodozyma and is selected from the group consisting of SEQ ID NO:1, an isocoding variant of SEQ ID NO:1, and a derivative of a SEQ ID NO:1 having an addition, insertion, deletion and/or substitution of one or more nucleotide(s).
 8. A vector or plasmid comprising a DNA sequence according to claim
 1. 9. A host cell transformed or transfected with a DNA sequence according to claim
 1. 10. A host cell transformed or transfected with a vector or plasmid according to claim
 8. 11. A process for producing an enzyme for converting acetyl Co—A to isopentyl pyrophosphate, which enzyme is in the mevalonate biosynthetic pathway or for converting isopentyl pyrophosphate to farnesyl pyrophosphate, which comprises culturing a host cell according to claim 9 or 10, under conditions wherein the enzyme is produced.
 12. A process for the production of isoprenoids or carotenoids, which comprise growing a host cell according to claim 9 or 10 under conditions wherein isoprenoids or carotenoids are produced.
 13. A process according to claim 12 wherein the carotenoid is astaxanthin.
 14. An isolated DNA sequence comprising a DNA sequence that does not hybridize to SEQ ID NO:1 but which encodes an amino acid sequence that is identical to SEQ ID NO:6. 